The 


MECHANICS 
I  y..^—..^.      ..    A 

IS 


COMPISIB 


Processes  for  Arti 

In  Every  Trade  « .*  <t 


K.  Wl  N  i 


GIFT  OF 
.V.  K.  '^interhalter 


UNIVERSITY  FARM 


R  E  V I  SEP  UP-TO-DATE  EDIT  I  ON 
THE 

Mechanics' 
Complete  Library 

OF     , 

MODERN  RULES,  FACTS,  PROCESSES,  ETC, 

Facts  About  Electricity— How  to  Make  and  Run  Dynamos— 
All  About  Batteries,  Telephones,  Electric  Railways  and 
Lighting— Engineering  Explained— Rules  for  the  In- 
struction of  Engineers,  Firemen,  flachinists 
Mechanics.  Artisians  and  all  Craftsmen- 
Tables  of   Alloy  -Useful  Recipes— In- 
formation Concerning  Glass,  fletal, 
Wood  Working,  Leather,  Arti- 
ficial Ice-making,  Chemical 
Experiments,    Glossary 
of  Technical  Terms, 
Etc.,  Etc. 


FIVE  BOOKS  IN  ONE 


^w       COMPILED   BY 

THOMAS  F.  EDISON  A.M.,  and  CHARLES  J.  WESTINGHOUSE 


COPYRIGHT,  1890,  BY  LAIRD  &  LEE 
COPYRIGHT.  1895.  BY  LAIRD  &  LEE 


CHICAGO 

LAIRD  &  LEE,  Publishers. 

1897. 


CONTENTS. 

Accidents  by  Shafting,  to  prevent 130 

Accidents  from  Running  Machinery,  prevention  of 127-130 

Accidents,  how  to  prevent 147 

A'r-Brake,  Westinghouse  Automatic 39-  74 

Alloy,  a  new 226,  284 

Alloys  and  Solders i8d 

Alloys,  table  of  principal 424 

Altitude  above  the  sea  level  of  various  places  in  the  United  States  424 

Aluminum,  how  to  solder 368 

American  Steamers,  fast 189 

Ampere  the  (electrical  measure) 538 

Ampere' s  Rule 487 

Analysis  of  Boiler  Incrustations 155 

"  Ancient "  Winters 559 

Apprentice^points  for 301 

Architects,  laws  effecting. . .  '. 442 

Architects,  etc.,  pointers  for 420,  421 

Areas  of  Circles " 351 

Armor  Plates,  tests  of 215 

Artesian  Wells,  valuable 344 

Ash  Sifter,  how  made 382 

Atmosphere,  effects  on  bricks 437 

Atmosphere,  estimated  mean  pressure 55 

Automatic  Sprinklers,  care  of 185 

Avoirdupois  weight 356 

Babbitt  Metal,  composition  of 369 

Ball,  cast  iron,  weight  of 282 

Ball,  how  to  turn  a 209 

Bank  of  England  Doors,  the 560 

Barrels,  how  made 234 

Basswood  Moldings 445 

Batteries,  closed  circuit  (electrical) 536 

Batteries,  electric 536 

Batteries,  galvanic 536 

Batteries,  open  circuit  (electrical) 536 


Batteries,  primary  (electrical) ^ 536 

Batteries,  storage  or  secondary  (electrical) 537 

Batteries,  voltaic 536 

Bell  Time  on  Shipboard 555 

Belting,  camel's  hair 289 

Belting,  how  to  calculate'speed 332 

Belting,  notes  on 80 

Belting  —Rules , 80-82 

Bessemer  Process,  real  inventor  of 220 

Blowing  Off  Under  Pressure 152 

Boilers  (see  Steam  Boilers) 45 

Boiler  Circumferences,  points  on 88 

Boilers,  Steam 45 

Boiler  Tubes,  cleaning .- 155 

Boiling 145 

Bolts,  weight  per  100 207 

Brass,  cleaning 155 

Brass,  its  treatment -  -323~~325 

Brass,  how  to  lacquer 219 

Brass  Castings,  hard  and  ductile 186 

Brass,  weight  of  sheet 196,  197 

Breaking  Strains  of  Metals 282 

Bricks,  effects  of  atmosphere  upon 437 

Bricks,  made  from  refuse  of  slate  quarries 337 

Bricks,  number  of,  to  construct  building 439 

Hand  Saw,  how  to  select  a  292 

Bronze,  how  to  make  malleable 288 

Building  Blocks  Made  of  Corn  Cobs 445 

Builders,  points  for 411-413 

Buying  Oil  and  Coal 317 

Cables,  submarine 278-282 

Calcimine,  how  to  prepare 445 

Calking - 3M 

CamePs  Hair  Belting 285-289 

Cans,  flat- top,  size  and  weight 4^ 

Carpenters,  number  m  London,  etc 337 

Cast  Iron  Columns 3^7 

Cast  Iron  Columns,  safe  load  for. , 349>  35° 

Cast  Iron  Columns,  safety  load •  .362-364 

Cast  Iron  Columns,  weight  of 353>  354 


Cast  Iron  Piles,  ar^on  of  sea-water 210 

Cast  Iron  Pipes,  weight  of. 410 

Cast  Iron,  weight  of  per  lineal  fov.\v 205 

Cathedrals,  dimensions  of 44! 

Celluloid  Sheathing ^5 

Cement,  a  new 284 

Cement,  a  reliable 446 

Cement,  as  used  in  Paris 044 

Cement  for  Granite  Monuments 304 

Cements,  useful ^4 

Centigrade  and  Metrical  Equivalents 283 

Chicago  Auditorium,  description 416-418 

Chimneys,  how  to  cure  smoky 459-461 

Chimney,  one  that  will  draw 369 

Chimneys,  sweating  of 4-8 

Chimneys,  table  of go 

Chinese  Cash 4r4 

China,  cost  of  living  in 367 

Chisels,  Cold 75-  77 

Circles,  area  of '."...     35 r 

Circles,  circumferences  of ^52 

Cisterns,  cylindrical,  capacity  of 292 

Cisterns,  cylindrical,  capacity  per  foot 365- 

Cleaning   Brass x  -$ 

Clock  Movement,  self-winding 307-310 

Closed  Circuit  Batteries  (electrical) 536 

Coal,  a  large  lump  of 2Q7 

Coal,  consumption  of  by  railroads 430 

Coal,  how  combustion  is  produced 291 

Coaling  Ships  in  West  1  ndies 384 

Coal,  steam x^i 

Coins  of  Different  Countries x  72,   1 73 

leather,  making  japanned 218 

Colors,  suggestions  for 441 

Cold  Chisels 75-  77 

Combustibility  of  Iron  Proved 271 

Combustion,  spontaneous 136-139,  297 

Combustion,  spontaneous,  liable  to 291 

Common  Names  of  Chemical  Substances 563 

Compass — Why  it  varies 227 

Conductors    (electrical) 535 

Copper,  deoxidized  . . .  .^ 217 


Copper,  tenacity  and  loss 336 

Copper,  weight  of  sheet 196,  197 

Corliss  Engine  Valves,  how  to  adjust 27 

Counter-boring,  tool   for 311 

Crystallized  Tin  Plates 373 

Cubic  Measure 355 

Cube  Roots,  tables  of 107-110 

Dam,  largest  in  the  world 559 

Dampers,  Oval 400 

Deafness  caused  by  Electric  Lights 297 

Deep  Soundings  near  Friendly  Islands 414 

Decimal  Equivalents 187 

Decimal  Equivalents  for  inches,  feet,  etc 442 

Decimal  Equivalents  for  ounces  and  pounds 442 

Deoxidized  Copper 217 

Dies,  metal  working 326-331 

Definitions  and  useful  terms 91 

Dry  Rot  in  Timber 429 

Dynamo,  the,  how  to  make  one 478-531 

What  a  Dynamo  is 478 

Faraday's  Discovery 478 

The  Galvanometer 479 

How  to  make  one *. 479 

Permanent  Magnets 481 

Testing  the  Galvanometer 482 

Experiments  with  one 483 

Experiments  with  a  Magnet 485 

The  Magnetic  Poles 486 

Currents  produce  Magnetism 486 

Ampere's  Rule 487 

The  first  Dynamo 488 

Clarke' s  Dynamo 489 

Function  of  the  Commutator 490 

Hjorth's  Dynamo 492 

Sieman's  Armature 493 

Currents  not  Continuous 494 

Magnetism  produces  Heat 495 

Pacinotti's  Ring  Armature , 496 

Patterns  for  a  Dynamo 497 

Pattern  for  Armature 498 

Drawings  for  Armature $09 


Patterns  for  Field  Magnets 501 

Drawings  for  Field  Magnets 500-503 

Patterns  for  Standard 504 

Drawings  for  Standard 504 

The  Castings 505 

Assembling  the  Castings 506 

The  Bearings 510 

The  Commutator 513 

The  Driving  Gear 516 

Wiring  the  Dynamo, 518 

Wiring  the  Armature 518 

Wiring  the  Field  Magnets 520 

Attachment  of  Wires 525 

The  Brushes 526 

Binding  Screws  and  Connections 528 

The  Complete  Dynamo 531 

Dynamo,  the,  what  it  is 478 

Dynamo,  Management  of  the 532 

Eccentric,  Locomotive,  how  to  set 89 

Economy  in  Use  of  Injectors 131 

Eiffel  Tower,  the 437 

Elbow,  four  piece,  to  describe  a  pattern  for 383 

Elbow  Angles,  table  of  height 380 

Electric  Batteries  (see  batteries) 536 

Electric  Experiments 536 

Electrical  Measurements 538 

Electricity,  development  of 211 

Electricity  Developed  by  Chemical  Action 535 

Electricity  Simplified 533 

Electricity,  frictional 534 

Electricity,  negative 534 

Electricity,  positive 534 

Electricity,  voltaic  and  galvanic 535 

Electricity,  what  is  it? 535 

Electric  Hand  Lantern 242 

Electric  Lights  in  Germany 45b 

Electric  Lights,  largest  in  the  world 476 

Electric  Light,  some  figures - .  238 

Electric  Machine 535 

Electric  Railroad 282 

Electric  Street  Railways,  cost  of 228 


8 

Electro-Magnetism 486 

Emery  Wheels,  value  of 273 

Engines  (see  Steam  Engines) 23 

Engines,  comparative  economy  of  high  and  low  speed 116 

Engines,  manipulation  of  new 167 

Engines,  triple  expansion 168 

Engine,  use  of  Indicator 30-  42 

Engineers,  a  warning  to 189 

Engineers,  pointers  for. ." 169 

Engineers,  valuable  information  for 161 

Experiment,  an  interesting 319 

Experiment,  electrical 536 

Explosion  of  Hot  Water  Boiler 391-394 

Explosions,  boiler  in  Germany 185 

Expansion  of  Substances  by  Heat 206 

Eve  Trough,  making 379 

Feed  Water  Heaters 84 

Ferrules,  how  to  draw 305 

Figures,  valuable 448 

Filter,  a  cheap 368 

Fire  Grate  Surface,  rule  for  finding 47 

Firemen,  rules  for   140 

Fire  Proofing  Wood  Work 440 

Flange  Joint,  how  to  make  a  strong 122 

Flaring  Articles  with  Round  Corners 376-379 

Flaring  Oval  Articles,  patterns  for 375,  376 

F!  :xible  Glass 237 

Floor,  how  to  make  a  good 425 

Floors,  how  to  wax 338 

Floors,  painting 430 

Floors,  painting  and  varnishing 456 

Flower  Stand,  a  wire 385 

Foaming  in  Boilers 144 

Forests  of  the  United  States 423 

Forth  Bridge,  description  of  the  new 558 

French  Cubic  Measure 355 

French  Long  Measure 358 

French  Square  Measure 357 

French  Weights '. 356 

Friction  of  Water  in  Pipes 55 

Fuel,  heating  powers  of 211 


Funnel  Marks  of  the  Principal  Atlantic  and  Transatlantic  Steam- 
ship Lines 554 

Furnaces,  facts  about 461 

Galvanic  Batteries 536 

Galvanic  Electricity 536 

Galvanometer,  the 479 

Galvanometer,  ho\v  to  make 479-483 

Gamboge,  how  prepared 562 

Gas  for  Locomotives 165 

Gas  Leakage,  how  to  detect  it 555 

Gauges,  Railway  .    170 

Gauges,  Steam 146 

Gear  Teeth,  how  to  prevent  breaking 269 

Gearing,  high  speed 290 

Geometry,  practical  for  mechanics 98 

Glass  Cutting  by  Electricity 296 

Glass,  flexible 237 

Glass,  frosted.. .- 448 

Glass,  how  to  perforate 289 

Glossary  of  Technical  Terms 565 

Glue  for  Damp  Places 426 

Glue,  on  the  use  of 436 

Glue  Paint  for  Kitchen  Floors 436 

Granite,  polishing 342 

Graphite,  in  steam  fitting , 141 

Grindstone,  how  to  make  a  small .-.•„, 79 

Grindstone  Quarries 344 

Grindstones,  to  find  weight  of. 423 

Gun  Barrels,  browning  them _ 297 

Guns,  large  ones  made 296 

Hand-hole  P lates 145 

Hardware  in  Havana... 373 

Heat,  amount  of,  required  to  melt  wrought  iron 268 

Heat,  divisions  of  degrees 160 

Heat,  expansion  of  substances  by 206 

Heat  Produced  by  Rapid  Magnetization 495 

Heat-proof  Paints 408 

Heat,  what  is  latent  heat? , . . .  157 

Heating  and  Ventilation 386-390 

Heating  Power  of  Fuel 2x1 


Heating,  steam 154 

Heating,  steam  -vs.  hot  water 462-464 

Heating  Surface  of  Boilers 47 

Heating  Surface,  steam  radiators 369 

High-speed  Gearing 290 

Hip  Bath  in  Two  Pieces: 406,  407 

Horse-power  of  Belting 82 

Horse-power,  nominal,  indicated,  effective 142 

Horse-power  of  Steam  Boilers  — 46,     47 

Horse-power  of  Steam  Engines 23,   1 30 

Horses,  Strength  of 559 

Hot  Water  Systems 368 

How  to  CaSt.  a  Face 284 

Hudson  Bay  Company 344 

Ice  House,  how  to  build 444 

Incrustations  of  Steam  Boiler 146 

Indicator,  Steam  Engine 30-  42 

Indicator,  description 30 

Indicator,  method  of  indicating 31 

Indicator,  driving  rigging 32 

Indicator,  diagrams     34 

Indicator,  uses  of 35 

Indicator,  tables  for 39 

Indicator,  taking  diagrams 40 

Indicator,  special  instructions 41 

Indicator,  computing  horse-power 42 

Injector,  economy  in  the  use  of. 131 

Injectors,  how  to  set  up 53 

Injectors,  suggestions  regarding 53 

Insulators  (electrical) 535 

Iron  and  Steel,  average  breaking  strain 159 

Iron  and  Steel  Making  in  India 275 

Iron  Brick 428 

Iron  Castings,  facts  about , 23  c 

Iron  Castings,  how  to  bronze 336 

Iron,  combustibility  of,  proved 271 

Iron,  different  colors,  caused  by  heat 305 

Iron,  flat-rolled,  weight  per  foot 198-203 

Iron,  how  it  breaks 272 

Iron  in  the  Congo 296 

Iron,  Russian  sheet 474 


II 

Iron,  new  method  of  bronzing 473 

Iron,  painting  of. 

Iron,  removing  rust 

Iron,  weight  and  areas  of I9C 

Iron,  weigh  t  of  sheet 196,19? 

Isinglass,  facts  about * 

Ivory  Gloss,  how  to  put  on  wood 3j 

Japanese  Lacquer  for  Iron  Ship* 5 

Japanese  Water  Pipes • 2I 

Lacquer,  Japanese,  for  iron  ships 2- 

Lap  on  Slide  Valves "" 

Latent  Heat,  what  is  it? 

Lathe,  how  to  gear  for  screw-cutting 3 

Lathe  Tools  for  Metals 

Law  Affecting  Architects 4J 

Law  of  Proportion  in  Steam  Boilers •  •  ie 

Law,  Swiss  Patent 277 

Lead,  ancient  use  of. 

Lead  on  Roofs  and  in  Sinks 35 

Lead  Pipes,  caliber  and  weight * 

Leather,  new  substitute  for ^ 

Lightning  Rods,  uselessness  of 5* 

Lock ,  largest  in  the  world 5  2 

Telephones • ;••;•_; •"•  *jj* 

Locomotive,  an  experiment  with  one. ....:.- 

Locomotive,  eccentric,  how  to  set * 

Locomotive,  gas  for .    

Ice  Making,  artificial I74 

Locomotives  in  1832  and  1888 74 

ocg 

Long  Measure 

Lubricating  without  oil • 3' 

Lumber  Measurement  Tables 

Lumber,  oak,  care  of 

Machinery,  prevention  of  accidents  by I27 


12 

Machinery,  care  of 143 

Magnetic  Poles,  north  and  south 480 

Magnets , 486 

Magnetism 531 

Magnetism,  Electro 531-478 

Magnetism,  effect  on  watches 230-234 

Magnetism,  Faraday's  discovery 478 

Magnetization,  rapid,  produces  heat 495 

Mahogany,  value  of 341 

Malleable  Iron,  to  tin 370 

Management  of  a  Dynamo 532 

Manilla  Rope  Transmission 184 

Mathematics,  definitions  and  useful  numbers 91 

Measures  of  Different  Countries 171 

Measurements,  electrical 538 

Melting  Points  of  Metals 285 

Mensuration 94 

Metals,  meltings  points  of 285 

Metals,  value  of. 287 

Metrical  and  Centrigrade  Equivalents 283 

Mica,  uses  of .  .*. 468 

Mineral  Wool 225 

Mitering,  perfect 449-451 

Miter,  to  describe  a 382 

Molders,  a  Valuable  point  for 283 

Monetary  Units  and  Standard  Coins  of  Different  Countries...  172,  173 

Mortar  Making 427 

Mud  Drums,  pitting  of 159 

Nails,  ten-penny,  what  a  pound  will  do 427 

Nails,  number  of,  in  a  pound 337 

Natural  Gas,  use  of,  in  cupolas 284 

Nickel  Plating 226 

Nickel  Plating  Solution 226 

Nickel  Plating,  to  polish 374 

Non-conductors   (electrical) 535 

Non-magnetizable  Watches 218 

Novel  Drawing  Instrument 403 

Nuts,  square,  number  in  a  keg 268 

Nuts,  hexagon,  number  in  a  keg 269 

Oak  Lumber,  care  of 339 


13 

"  Of  Course,"  for  engineers 26 

Ohm,  the  (electrical) 53^ 

Oil  and  Coal  Buying 3J7 

Old  Tins  No  Longer  Useless v 37* 

Open  Circuit  Batteries  (electrical) 536 

Oval  Damper,  how  to  make 4°° 

Oval  of  Any  Length,  how  to  strike 385 

QV  . ;    «,v^,  S<2.v,9/:e  aa<i  Circle 39° 

Paint,  a  durable  black - 4°7 

Paint,  a  valuable  preservative *°° 

Paint,  heat  proof 4°8 

Paint  Work 4l8 

Painting  Floors 43° 

Paper  Holder,  an  ornamental.. 3°6 

Paper  Makers,  valuable  points  for 5.6* 

Patent  Office,  United  States,  rules  and  regulations 545 

PATENTS,  a  few  points  for  inventors  regarding 545 

Correspondence  with  Patent  Office 545 

Applicants 545 

In  case  of  death  of  inventor 54^ 

In  case  Patent  is  assigned 54° 

Joint  inventors 54$ 

Foreign  Patents 54° 

The  Application - 546 

The  Petition 547 

The  Specification 547 

The  Oath 548 

The  Drawings 549 

Kind  of  paper 549 

Size  of  sheet 549 

Regarding  Drawings 55° 

The  Scale 55<> 

The  Model 55* 

Attorneys 551 

Patent  Office  Fees 55* 

Patent  Laws,  Swiss 277 

Patterns  for  a  Dynamo 497~5°5 

Pattern  for  a  Tapering  Square  Article 4°4 

Pattern  for  a  T  Joint 4°* 

Patterns,  how  to  mend 2* 

Pattern  Making,  hints  on 2& 


Pattern  Making,  notes  on 3!g 

Pavements 447 

Pipes,  cold  water  supply 431-434 

Pipes,  cast  iron,  weight  of 410 

Pipes,  lead,  caliber  and  weight . ' 334 

Pipes,  steam,  a  non-conducting  coating  for 134 

Pipes,  to  find  amount  for  heating  buildings 434 

Pipes,  how  to  thaw  out 126 

Pipes,  steel,  tests   of 310 

Plane  Iron,  how  to  sharpen 340 

Planing    Machines 22} 

Plaster,    a   new  wall 446 

Plastering,  estimating  cost  of. 413 

Plaster  for  Moldings 457 

Pointers  for  Success  in  Business 556 

Poles,  the  magnetic 480 

Power,  transmitting  by  vacuum : .  136 

Pressure,  atmospheric  mean 55 

Primary  Batteries  (electrical)    536 

Principles  of  Boiler  Construction 148 

Proportions  for  Steam  Boilers 166 

Proof  of  the  Earth's  Motion 227 

Proposed  Engineering  Feat 435 

Pulleys,  rule  for  width  and  diameter 82 

Pumps  (see  Steam  Pump) 54 

Pumice  Stone,  how  made 266 

Rails,  steel 350 

Railroads,  consumption  of  coal „ 430 

Railroads,  electric,  in  Japan 325 

Railroad,  electric,  largest  in  country 282 

Railroad  Signals 183 

Railway  Gauges  of  the  World 170 

Railway  Transit,  rapid 134 

Redwood  Finish 446 

Reservoir,  tapering,  round-cornered  one .  401 

Rivets,  boiler,  number  per  loo-pound  keg 336 

Rivets,  weight  of 204 

Rock,  cost  of  excavating - . .  428 

Roof  Framing,  hip  and  valley. 455 

Rope,  how  to  select 293 

Rope,  length  per  coil,  and  weight 288 


15 

Rope  Transmission  in  England 4 

Rot  in  Timbers _ 43 

Rule  to  find  area  steam  piston  of  pumps 56 

Rules  for  Belting: 

To  find  length  and  width 80 

To  calculate  horse-power 82 

To  find  width  of  pulley 8» 

To  find  diameter  of  pulley 82 

To  find  number  of  revolutions 82 

Rule— To  find  capacity  of  water  cylinder  of  pumps 56 

Rule— To  find  diameter  of  cylinder  for  required  horse-power.  24 

Rule — To  find  diameter  pump  cylinder 55 

Rule — General  rule  for  all  classes  of  boilers 49 

Rule— To  find  height  for  discharging  given  quantity  of  water.  51 

Rule— To  find  fire  grate  surface  of  boiler 47 

Rule — To  find  fire  grate  surface  of  locomotive  boiler 47 

Rule— To  find  heating  surface  boiler 47 

Rule— To  find  heating  surface  of  locomotive  boiler 47 

Rule — To  find  horse-power  of  boiler 46 

Rule— To  find  horse-power  locomotive  boiler 47 

Rule— To  find  indicated  horse-power  of  engines 24 

Rule — To  determine  lap  on  steam  side  slide  valve 25 

Rule— To  find  horse-power  for  elevating  water ,56 

Rule— To  find  quantity  of  water  to  be  discharged 56 

Rule— To  find  quantity  water  elevated 55 

Rule — To  find  pressure  of  a  column  of  water 54 

Rule— To  find  size  orifice  to  discharge  given  quantities  water  56 

Rule  for  Firemen  • 140 

Rules  and  Regulations  for  Properly  Wiring  and  Installing 

Electric  Light  Plants 539 

Moisture  danger 539 

Earth  danger 540 

Ignorance,  etc • 540 

Consulting  Engineer 540 

Conductors 540 

Sectional  area 540 

Acr  ^sibility 540 

Insulate  *  • 540 

Maximum  tei.  ~^ature . 540 

Distance  apart « 541 

Inflammable  structures 541 


i6 

Metallic  armor « ...  541 

Joints , . . . . , , 541 

Gas  and  water  pipes 541 

Overhead  conductors . 541 

Lightning  protectors . 541 

Insulation  resistance . . 542 

Switches 542 

Construction  and  action , . 542 

Insulating   handles ,  542 

Main  switches 542 

Switch  boards 542 

Electrical   fitting , .....    54* 

Cut  outs » , . . 543 

Imperative  use  of 543 

Situation « . .  T . . . .  - . 543 

Portable  fittings . . . 543 

Arc  lamps „.„...<.. 543 

The  dynamo. ....... 544 

Batteries ,     .. .. 544 

Maintenance „ . . .  544 

General ......... 544 

Rust,  how  to  remove  from  iron .  „ 222 

Rust-Proof  Wrapping  Paper.  ....«....=. . . . . , 406 

Rusty  Steel,  to  clean ...  ,...<= . , .  c . . .  < *..<>.....;..,-.  238 

Safety  Valves .  c „......„. . . . «. , . . ........ . .  .49,  50 

Safety  Valve,  rule  for  weights c ...  c ..........  119 

Saturated  Steam,  properties  of.  , . ...... .0 150 

Screw  Auger,  inventor  of 405 

Screw  Cutting,  how  to  gear  a  lathe  for no 

Screw  Drivers,  an  improved ......  229 

Screw  Heads,  how  to  bury  out  of  sight. 455 

Screw  Making  at  Providence , 298-300 

Screw  Threads,  table  of  gears  for  cutting. ......  c 243-264 

Sea  Water,  action  of  on,  cast  iron  piles. ...» ..Oo..ot ..............  210 

Watch,  facts  about 325 

Shafting,  accidents  by 130 

Shafting,  an  easy  way  to  level « 307 

Shafting,  belting  at  right  angles .....«, .„ 306 

Shafting,  things  to  remember. ........o..o..0eo.eooec..o.  ....320    321 

Sheathing  celluloid  . o........... 135 

Shingles,  to  calculate  number  of.. .»...„ „<>. 44- 


Shop  Kinks,  useful , .  .T 395-398 

Signals,  railway 183 

Sleepers  Used  by  World's  Railroads 409 

Slide  Valves,  how  to  set 24 

Slide  Valves,  setting  of 87 

Smoke,  how  formed 156 

Smokey  Chimneys,  how  to  cure    459-461 

Soda  Ash  in  Boilers 150 

Soldering 4jn 

Solder,  cold 370 

Solders  and  Alloys 186 

Soldering,  points  on ......   473 

Specific  Gravity,  table  of i-4 

Spindle-milling  Machine 390 

Spontaneous  Combustion 136-297 

Spontaneous  Combustion,  liable  to 291 

Square  Measure 357 

Square  Roots,  table  of 107-1 10 

Steam  as  a  Cleansing  Agent 168 

Steam,  an  invisible  gas 126 

STEAM  BOILERS,  analysis  of  incrustations 155 

Boiling 145 

Blowing  off  under  pressure 152 

Care  of 55 

Calking 124 

Cleaning  tubes 155 

Foaming 144 

Hand-hole  plates .    145 

Horse  power  •:'. 46 

How  plates  are  proved 179 

How  to  prevent  accidents 147 

How  to  test 162 

Importaant  to  those  operating 147 

Incrustations  of 146 

Kinds  of 45 

Largest  in  America 122 

Law  of  proportions 160 

Marine 47 

Mistakes  in  designing 158 

Principles  of  construction 148 

Proportions  for, 166 

Rules  for 47,     32 


iS 

Safe  working  pressure  flues 184 

Scale  in 163 

Stopping  with  a  heavy  fire 154 

Table  of  safe  working  pressure 153 

Testing  plates 166 

The  total  pressure . ." 152 

Treatment  of. 115 

Tubular 47 

Weight  of  circular  heads 335 

Steam  Coal 151 

Steam  Engine 23 

Actual  horse  power 23 

Comparative  economy  high  and  low  speed 1 16 

Corliss  valves,  how  to  adj  ust 27 

Expansion  by  lap 25 

Future  of 164 

Horse-powers 23,  142,  143 

Indicated  Horse-power 23 

Indicator 30-  42 

Manipulation  of  new 162 

Mean  pressure  in  cylinder ..     23 

Nominal  horse-power 23 

Rules 23  25 

Slide  valves,  how  to  set 24 

Slide  valves,  setting  of. 87 

Theory  of 112 

The  world's 290 

Triple   expansion 168 

Steam  Fitting,  use  of  graphite 141 

Steam  for  Heating 58 

Steam  Gauges 146 

Steam  Heating 154 

Steam  Radiators,  heating  surface  of 369 

Steam  Pipes,  for  heating  buildings 434 

Steam  Pipes,  how  to  thaw  out 126 

Steam,  properties  of  saturated 150 

Steam  Pumps,  suggestions 54 

Steam  Pumps,  to  find  diameter  cylinder 55 

Steam  Pumps,  to  find  quantity  Water  elevated ...    .     55 

Steam,  super-heated 146 

Steam  vs.  Hot  Water  Heating 462-464 


19 

Steamers,  Fast  American 189 

Steel,  chemical  or  physical  tests  for 212 

Steel,  how  to  anneal 223 

Steel,  notes  on  working  of 267 

Steel,  to  clean  rusty 238 

Steel  Pipe,  tests  of 310 

Steel  Punches,  tempering 208 

Steel  Rails,  used  as  girders 350 

Steel  Sleepers,  rivetless 184 

Steel  Square,  ho\v  to  use 372 

Steel,  suggestions  to  workers 213 

Steel,  the  secret  of  cast  steel 274 

Steel,  weight  of  sheet 196,  197 

Steel,  when  hardened 139 

Steel,  why  hard  to  weld 304 

Stone,  natural  and  artificial 365 

Stone,  crushing  strain 365 

Storage  Battery,  how  to  -make  one 312 

Storage  or  Secondary  Battery 537 

Strainer,  rain  water '.....  399 

Street  Railways,  electric 22? 

Strength  of  Materials 359-361 

Switching  from  an  Engine  Cab 183 

Submarine  Cables 278-282 

Superheated  Steam 146 

Surveying  Measures 358 

Sycamore 439 

Tables, 

Alloys , 424 

Chimneys 90 

Heating  surface  per  horse-power 46 

Cube  and  square  roots 107-116 

Density  of  water 123 

Diameters,  high  and  low  pressure  Cylinders 122 

Difference  of  time  from  New  York 180-182 

Friction  of  water  in  pipes 55 

Horse-Power  transmitted  by  belts 120,  121 

Lap  according  to  travel  slide  valve 25 

Length  and  number  tacks  per  pound 182 

Proportions  cylinder  tubular  boilers 48 

Properties    saturated  steam 150 


Safe  working  pressure  iron  boilers 153 

Safety-valves,  capacity 51 

Chimneys,  regard  to  horse-power 90 

Size,  capacity  standard  puuws   ...     57 

Saving  by  feed  water  heater .       %b 

Specific  gravity lOo 

Square  and  Cube  roots 107-1 10 

Strength  belting  material 83 

Universal   taps 265,  266 

Tacks,  length  and  number  per  pound 182 

Tanks,  how  to  calculate  capacity 335 

Taps,  universal,  table  for  making 265,  266 

Temperature,  indicated  by  color  of  flame 49 

Tempering  Steel  Punches 208 

Testing  Armor  Plates 215 

Testing  Boiler  Plates 166 

Te^eing  Exterior  Stains 444 

Tests  for  steel,  chemical  or  physical 212 

Thermometers,  how  made 300 

Thermometer  Scales 302,  304 

Thermal  Unit/^jxplanation  of . .   155 

Theory  of  Steam  Engine 112 

Things  That  Will  Never  Be  Settled 293 

Things  Worth  Knowing 294 

Timber,  a  colossal  stick  of 457 

Timber,  dry  rot  in 429 

Timber,  in  favor  of  small 343 

Timber,  properties  of 366 

Timber,  rot   in 438 

Timber,  seasoning 435 

Time,  difference  from  New  York „ 180-182 

Tin,  modern  uses  of. 466-468 

Tin  Plates,  crystallized 373 

Tin  Plates,  endless 373 

Tin,  sizes  and  weights  of 333 

Tinning  by  simple  immersion. . .  „    434 

Tinning,  improved  process  of 469 

Tool  for  counter-boring 311 

Tools,  how  to  anneal  small 187 

Tools,  how  to  detect  iron  and  steel 173 

Tools,  how  to  keep 229 

Tools,  lathe  for  metals 77 


21 

Tracing   Paper,  how  to  make 208 

Trees,  the  annual  ring  in 419 

Tubes,  solid  drawn 224 

Turning  or  Lathe  Tools  for  .Metal 77 

Universal  Taps 265-266 

Useful  Cements 134 

Useful  Numbers 3*5-317 

Useful  Numbers  and  Definitions 91 

Useful  Receipts 374 

Useful  Shop  Kinks « 395-398 

Vacuum,  transmitting  power  by 136 

Valuable  Figures 448 

Various  Locations  of  the  Capital  of  the  United  States 557 

Varnish,  to  make  it  adhere  to  metals 282 

Varnish,  removal  of  old 441 

Varnishing  and  Painting  Floors 456 

Ventilation  and  Heating 386-390 

Ventilation  of  Buildings 451-454 

Ventilation,  hints  on ,  .  422 

Vibration,  how  to  overcome 185 

Volt,  the  (electrical) 538 

Voltaic  Electricity 536 

Voltaic  Batteries  (electrical) 536 

Common  Woods,  tensile  strength  of. 208 

Watch  and  Learn .    216 

Watches,  effect  of  magnetism  upon 230 

Leather,  making  japanned 218 

Watch  Wheels,  number  of  revolutions 283 

Water,  density  of 123 

Water,  friction  of  in  pipes 55 

Water,  simple  tests  for 294 

Water,  useful  information  about 54 

Water  Pipes,  Japanese 210 

Weight,   avoirdupois 356 

Weight  of  Bolts  per  ico.    207 

Weight  of  Copper 196,  197 

Weight  'Cast  Iron  per  Lineal  Feet ^205 

Weight,  cubic  foot  substances 346-348 


Weights,  French -. 356 

Weight  of  Iron 190-195-196-197-108-203 

Weight  of  Rivets  and  round-headed  Bolts 204 

Weight  and  Specific  Gravity  Metals 286 

Weight  of  Sheet  Brass 196,  197 

Weight  oi  Sheet  Steel 196,  197 

Welding,  a  Russian  process 370 

Welland  Canal,  the • 561 

Wells,  artesian 344 

Leather,  making  japanned 218 

Westinghouse  Automatic  Brake 59 

Description 59 

Air  pump 6X 

Triple  valve 63 

Engineer' s  brake-valve 65 

Pump  governor 67 

Equalizing  valve 68 

Instructions 69 

How  to  apply 71 

How  to  release 71 

Brake  power 73 

Car  levers 74 

When  a  day's  work  begins : 289 

Hydraulic  Rams 564 

Window  Glass,  how  large  cylinders  are  cut 344 

Window  Glass,  number  lights  in  a  box  of  50  feet 270 

Wire  Manufacture,  new  process ., ., 409 

Wood,  a  polish  for 447 

Wood,  a  very  durable 443 

Wood,  preservation  by  lime 443 

Woods,  weight  of 333 

Wooden  Beams,  safe  load  for : 345 

Workshop  Jottings 322 

Wrapping  Paper,  rust-proof 406 

Zinc,  as  a  fire  extinguisher 381 

Zinc,  how  to  polish 4*4 


23 
THE  STEAM-ENGINE. 

The  term  "  Horse-power "  is  the  standard  measure  of 
power  as  applied  to  steam-engines.  This  unit  of  power  has 
been  adopted  by  all  manufacturers  of  steam-engines  in  all 
parts  or  the  world. 

The  term  originated  with  Watts,  the  so-called  inventor  of 
the  steam-engine.  He  demonstrated  that  a  horse  could  work 
8  hours  a  day  continuously,  traveling  at  the  rate  of  2^  miles 
an  hour,  raising  a  weight  of  150  pounds  ipo  feet  high  by 
means  of  a  block  and  tackle.  Reducing  this  to  equivalent 
terms,  a  horse  could  raise  150  pounds  at  the  rate  of  220  feet 
per  minute,  or  2j^  miles  an  hour,  or  33,000  pounds  one  foot 
per  minute.  Thus,  a  horse-power  is  the  power  required  to 
raise  33,000  pounds  one  foot  a  minute.  There  are  three 
kinds  of  horse-power  referred  to  in  connection  with  engines, 
*  nominal"  "indicated"  and  "actual" 

The  nominal  horse-power  is  found  by  multiplying  the  area 
of  the  piston  in  inches  by  the  average  pressure,  and  multiply- 
ing this  product  by  the  number  of  feet  the  piston  travels  in 
feet  per  minute,  then  dividing  this  last  product  by  33,000. 
The  quotient  will  be  the  nominal  horse-power  of  the  engine. 

The  indicated  horse- power  is  found  by  multiplying  together 
trie  mean  effective  pressure  in  the  cylinder  in  pounds  per 
square  inch,  the  area  of  the  piston  in  square  inches  and  the 
speed  of  the  piston  in  feet  per  minute,  and  dividing  the  prod- 
uct by  33,000. 

The  actual  horse-power  i»  the  indicated  horse-power 
minus  the  amount  expended  in  overc<  ming the  friction.  The 
following  is  a  general  rule  for  calcula  ing  the  horse-power  of 
an  engine: 

RULE. — Multiply  the  area  of  the  pi  ton  in  square  inches , 
the  mean  pressure  of  the  steam  on  the  nston  per  square  inch, 
and  the  velocity  of  the  piston  in  ft^.t  per  minute,  together^ 
and  divide  this  product  by  33,000.  7  \:  quotient  will  be  the 
horse-power. 

The   mean  pressure  in  the  cylinder,   when  cutting  off  at 

stroke,  equals  boiler  pressure  x  .597 
x  .670 
x  .743 

K  '        x  -847 

#  «.  x  .919 

x  %& 

x  .992 


24 

TO    FIND    THE    DIAMETER  OF   A   CYLINDER   OF   AN     ENGINE 
OF   A   REQUIRED    NOMINAL   HORSE-POWER. 

Divide  5, 500 by  the  velocity  of  the  piston  in  feet  per  minute, 
and  multiply  the  quotient  by  the  required  horse-power.  The 
product  will  be  the  area  of  piston  in  square  inches.  From 
this  the  diameter  can  be  obtained  by  referring  to  table  of  areas 
of  circles. 

TO    DETERMINE   THE   EFFECTIVE    POWER   OF    AN  ENGINE  BY 
AN  INDICATOR. 

Multiply  the  area  ot  the  piston  in  square  inches  by  the 
average  force  of  the  steam  in  pounds;  multiply  this  product  by 
the  velocity  of  the  piston  in  feet  per  minute  ;  divide  this  last 
product  by  33,000,  and  j70  of  the  quotient  will  be  the 
effective  power. 

The  travel  in  feet  of  a  piston  is  found  by  multiplying  the 
distance  it  travels  in  inches  for  one  stroke  by  the  whole 
number  of  strokes  per  minute.  Dividing  this  product  by  12 
gives  the  number  of  feet  the  piston  travels  per  minute. 

THE  SLIDE  VALVE. 

How  to  set  a  slide  valve. — Place  the  crank  at  the  center, 
and  the  eccentric  at  right  angles  with  the  crank;  then  put 
the  valve  in  the  center  of  its  travel,  and  the  rocker  plumb  at 
^ght  angles  with  both  cylinder  and  crank-pin ;  when  this  is 
«fone,  adjust  the  valve-gear  to  its  proper  length,  then  move 
the  eccentric  forward  until  the  valve  has  the  desired  amount 
of  lead;  make  the  eccentric  fast  in  this  position,  and  turn  the 
crank  around  to  the  other  center,  and  see  if  the  lead  is  equal; 
if  so,  the  engine  will  run  all  right.  In  case  the  lead  is  not 
equal,  equalize  it  by  moving  the  eccentric  slightly  back  and 
forth. 

Where  the  lead  is  unequal  on  account  of  wear,  the  travel 
of  the  valve  may  be  equalized  by  placing  lines  of  brass  or  tin 
behind  or  in  front  of  the  box  which  connects  the  valve-rod 
with  the  rocker.  The  "  outside  lap  "  means  steam  lap  ;  the 
"  inside  lap  "  means  exhaust  lap. 

To  compute  the  stroke  of  a  slide  valve. — To  twice  the  lap 
add  twice  the  width  of  a  steam  port  in  inches,  and  the  sum 
will  give  the  stroke  required. 

Half  the  throw  of  the  valve  should  be  at  least  equal  to  the 
lap  on  the  steam  side,  added  to  the  breadth  of  the  port.  If 
this  breadth  does  not  give  the  required  area  of  port,  the 
throw  of  the  valve  must  be  increased  until  the  required  area 
is  attained. 


25 

By  referring  to  the  following  table,  the  desired  lap  may  be 
found  if  the  travel  of  the  valve  is  known: 


Travel  of 
the  valve 
in  inches. 

The  travel  of  the  piston  where  the  steam 

is  cut  off. 

1       i       A      4 

\-'l                3 

I            1? 

The  required  I.AI-. 

22 

3 

31 

4 


I  £ 

if 

2 


2  i 


2ft 


44 


f 


1! 


1    4 


To  find  how  muck  lap  must  be  gii-en  on  (lie  steam  side  of 
a  slide  valve  to  cut  off  the  steam  at  any  given  part  of  f/ie 
stroke  of  the  piston.  —  From  the  length  of  stroke  of  the  piston 
subtract  the  length  of  the  stroke  that  is  to  be  made  before 
the  steam  is  cut  off;  divide  the  remainder  by  the  stroke  of  the 
piston,  and  extract  the  square  root  of  the  quotient;  multiply 
this  root  by  half  the  throw  of  the  valve;  from  the  product 
subtract  half  the  lead  and  the  remainder  will  give  the  lap 
required. 

Expansion  by  lap,  with  a  slide  valve  operated  by  an  eccen- 
tric alone,  cannot  be  extended  beyond  one-third  of  the  stroke 
of  a  piston  without  interfering  with  the  efficient  operation  of 
a  valve;  when  the  lap  is  increased,  the  throw  of  the  eccentric 
should  also  be  increased. 

The  lap  on  the  steam  side  must  always  be  greater  than 
that  on  the  exhaust  side,  and  this  difference  ruust  be  in- 
creased the  higher  the  velocity  of  the  piston,  for,  in  fast-run- 
ning engines,  also  in  locomotives,  it  is  necessary  that  the  ex- 
haust valve  should  open  before  the  end  of  the  stroke  of  the 
piston,  so  that  more  time  can  be  allowed  fur  the  escape  of 
steam. 


26 

"OF    COURSE"    FOR   ENGINEERS. 

Of  course  you  will  always  start  your  engine  slowly,  so  that 
the  air  and  water  condensation  can  be  expelled  from  your 
cold  cylinder;  then  you  will  gradually  bring  it  to  its  regular 
speed. 

Of  course  you  will  be  sure  to  keep  open  the  drip  cock, 
both  in  the  front  and  back  heads  of  the  cylinder,  when  the 
engine  is  standing  still,  and  never  close  them  until  all  the 
winter  has  dripped  out. 

Of  course  you  will  never  let  in  any  oil  or  tallow  to  your 
cylinder  until  it  is  made  hot  by  the  steam. 

Of  course  you  will  be  careful  not  to  put  in  too  much  oil  at 
any  time,  knowing,  as  you  do,  that  it  will  be  sent  to  the  feed- 
water  and  cause  your  boiler  to  prime  and  foam. 

Of  course  you  will  always  oil  up  before  starting  your 
engine. 

Of  course  you  will  always  keep  your  piston  and  valve-pack- 
ing in  a  bag  or  clean  drawer,  so  as  to  keep  sand,  dirt  or  other 
grit  from  becoming  attached  to  it,  and  so  cut  or  flute  the  rods. 

Of  course  you  will  not  use  new  waste  to  wipe  up  the  dirty 
oil  from  the  stub-ends,  crank-pins  or  cross-head  guides,  and 
then  use  the  same  waste  to  polish  --up  the  bright  and  finished 
work. 

Of  course  you  will  exercise  great  care  in  adjusting  the 
packing  in  steam-cylinders. 

Of  course  you  know  that  when  you  generally  pack  the 
piston  packing,  both  cylinder  and  packing  are  cold,  and  if  they 
are  screwed  or  wedged  in  very  tight  while  in  this  condition 
that  the  expansion,  when  exposed  to  the  heat  of  the  steam, 
will  induce  great  rigidity. 

Of  course  you  understand,  if  this  is  so,  the  oil  or  lubricat- 
ing substance  cannot  enter  between  the  surfaces  in  contact, 
and  that  great  friction,  heating  and  cutting  will  be  the  result. 

Of  course  you  are  aware  that  when  packing  loses  its  elas- 
ticity it  is  no  good,  and  should  be  removed. 

Of  course  you  know  that  piston  or  valve-rod  packing  should 
never  be  screwed  up  more  than  sufficient  to  prevent  it  from 
leaking,  and  that  the  softer  the  packing  the  longer  it  will  last 
and  the  better  your  engine  will  run. 

Of  course  yo'u  have  tried  that  little  trick  of  screwing  the 
packing  up  tight  when  it  is  first  inserted  in  the  boxes,  and 
then  slacking  the  nut  off  to  allow  the  packing  to  swell  when 
exposed  to  the  heat  of  the  stc  m 

Of  course  you  will  read  pages  53,  88,  90,  95,  97  and  103  in 
this  book. 


27 

HOW  TO  ADJUST    AND    SET    CORLISS    ENGP'S 
VALVES. 

The  original  crab-claw  valve-gear,  as  used  by  the  inventor, 
Geo.  H.  Corliss,  has  been  gradually  superseded  by  the  im- 
proved half-moon  valve-gear,  used  on  the  Reynold's  engine 
and  other  prominent  Corliss  engine  builders. 

This  difference  between  the  old  and  new  style  of  valve 
applies  only  to  the  steam-valves,  as,  in  both  cases,  the  ex- 
haust-valves open  toward  the  center  of  the  cylinder. 

In  the  Corliss  valve-gear  (sometimes  called  "detachable 
valve-gear")  the  action  of  the- steam-valves  is  positive,  the 
direct  action  of  the  working  parts  of  the  engine  opening 
them  at  the  proper  time,  and  keeping  them  open  until  the 
connection  with  the  engine  is  detached  or  broken,  and  the 
hook  tripped  by  the  working  of  the  cut-off  cams.  The  steam- 
valves  are  closed  by  vacuum  dash-pots  (sometimes  by  springs 
or  weights).  The  cut-off  is  automatic  and  is  determined  by 
the  lequirements  of  the  load  on  the  engine,  so  that  the  cut- 
off cams  do  not  always  trip  the  hook  at  the  same  point,  as 
they  are  moved  by  the  governor. 

To  those  unfamiliar  with  the  Corliss  valve-gear,  it  ap- 
pears a  very  complicated  affair,  yet,  in  reality  it  is  very  simple, 
and  is  more  easily  adjusted  than  the  ordinary  slide-valve. 

To  understand  the  simplicity  of  the  Corliss  valve-gear,  the 
four  valves  (two  steam,  two  exhaust),  must  be  considered  as 
the  four  parts — or  edges — of  the  common  slide-valve,  that 
is,  the  working  edges  of  the  two  steam- valves  are  equivalent 
to  the  two  steam  edges  of  the  slide-valve,  and  the  working 
edges  of  the  two  exhaust-valves  as  equivalent  to  the  exhaust 
edges  of  the  slide-valve. 

The  principle  is  the  same  in  the  two  styles  of  valves — 
Corliss  and  slide — but  the  difference  comes  in  the  adjustment, 
for  the  slide-valve  is  a  solid  valve,  and  any  adjustment  of  one 
part  affects  the  whole,  while  with  the  Corliss  valve  each 
part  is  susceptible  of  an  individual  and  separate  adjustment, 
which  can  be  made,  if  necessary,  while  the  engine  is  work- 
ing, without  shutting  down.  The  eccentric  works  the  valves, 
and  are  connected  with  them  on  the  Corliss  gear,  by  means 
of  the  wrist  plate,  cnrrier-arm,  rocker-arm  and  reach-rodj 

Besides  imparting  motion  to.  he  valves,  the  wrist-plate 
modifies  the  speed  of  travel  at  different  parts  of  the  stroke, 
giving  a  quick  and  accelerating  speed  when  opening  the 
steam-valve,  and  a  quick  opening  and  closing  of  the  exhaust- 


28 

valve,  botli  steam  and  exhaust-valves  being  at  their  slowest 
speed  when  closed. 

First,  remove  the  back-leads  or  back-caps  of  the  four  valve- 
chambers;  when  this  is  done  the  engineer  will  find  guide  lines 
on  the  ends  of  the  valves,  and  also  on  the  ends  of  the  valve- 
chambers.  The  lines  on  the  steam-valve  will  coincide  with 
the  working  edges  of  the  valve,  and  those  on  the  steam- valve 
chamber  with  the  working  edges  of  the  steam-ports.  Guide 
lines  will  also  be  found  on  the  exhaust- valves  and  ports. 

The  wrist-plate  is  located  on  the  valve-gear  side  of  the  cylin- 
der, in  a  central  position,  between  the  four  valve-chambers. 

On  the  stand,  which  is  bolted  to  the  cylinder,  will  be  found 
a  deeply  scribed  line,  and  on  the  hub  of  the  wrist-plate,  three 
other  lines,  which  show  the  center  of  the  wrist  plates,  and 
the  limits  of  its  travel  or  throw. 

To  adjust  the  valves,  the  reach-rod  which  connects  the 
wrist-plates  with  the  rocker-arm,  must  first  be  unhooked;  next 
place  the  wrist-plate  in  its  central  position  and  hold  it  there. 

All  the  connecting-rods  between  the  steam  and  exhaust 
valve-arms  and  the  wrist-plate,  are  made  with  right  and  left 
hand  threads  on  their  opposite  ends,  and  furnished  with  jamb- 
nuts,  so  that  the  rods  can  be  easily  lengthened  or  shortened 
by  merely  slacking  the  jamb-nuts  and  turning  the  rods. 

In  this  manner,  set  the  steam- valves  so  that  for  every  10 
inch  diameter  there  will  be  ^  inch  lap,  and  for  every  32 
inch  diameter  ]/2  inch  lap,  other  intermediate  diameters  in  pro- 
portion to  these  distances. 

Set  the  exhaust-valves  for  every  10  inch  diameter  of  cylin- 
der with  ~fa  inch  lap,  and  for  32  inch  diameter  J/£  inch  lap. 
Double  these  distances  for  condensing  engines. 

The  lines  on  the  valves  which  are  nearer  the  center  of  the 
cylinder  than  the  lines  on  the  valve-chambers  show  the  lap 
on  both  steam  and  exhaust  valves. 

After  the  valves  have  thus  been  adjusted,  turn  the  wrist- 
plate  to  the  extreme  limits  of  its  throw,  and  adjust  the  rods 
connecting  the  steam-valve  arms  with  the  dash-pots,  so  that, 
when  the  rod  is  down  as  far  as  it  will  go,  the  square  steel 
block  on  the  valve-arms  will  just  clear  the  shoulder  of  the 
hook.  The  adjustments  of  these  connecting  rods  must  be 
properly  made,  for  if  too  long  the  steam-valve  arm  will  be 
bent  or  broken,  and  if  too  short  the  valve  will  not  open,  be- 
cause the  hook  will  not  engage. 

Now  hook  the  engine  in,  loosen  the  eccentric  on  the  shaft, 
and  turn  it  over,  adjusting  (he  eccentric-rod  so  that  the  lines 


29 

on  the  hub  of  the  wrist-plate,  which  show  the  limits  of  its 
travel  and  throw,  will  coincide  with  the  line  scribed  on  the  stand. 
Place  the  crank  on  its  dead-center,  and  turn  the  eccentric 
in  the  direction  which  the  engine  is  to  run,  so  that  the  steam- 
valve  will  show  an  opening  of  ^  to  l/%  of  an  inch  (depending 
on  the  speed  at  which  the  engine  is  to  run — the  faster  the 
speed  the  more  lead  it  requires).  The  line  on  the  valve, 
which  is  nearer  the  end  of  the  cylinder  than  the  line  on  the 
valve- chamber,  shows  the  opening  required,  which  is  the 
"  lead  "  or  port  opening  when  the  engine  is  on  its  dead-center. 
Now  secure  the  eccentric,  or  the  shaft,  by  tightening  the  set- 
screw,  and  throw  the  engine  over  to  its  other  dead-center, 
carefully  noting  if  the  other  steam- valve  shows  the  same 
opening  or  lead.  If  it  does  not,  adjust  it  properly  by  length- 
ening or  shortening  the  connecting-rod  from  the  valve-arm  to 
the  wrist-plate. 

The  exhaust-valves  are  adjusted  in  the  same  manner. 
The  directions  just  given  are  for  the  half-moon  style  of  valve- 
gears,  which  open  from  the  center  of  the  cylinder.  In  cases 
of  the  crab-claw,  or  any  other  style  which  open  toward  the 
center  of  the  cylinder,  the  method  of  adjustment  is  the  same 
as  given  above;  but,  with  the  difference  that  the  lap  on  the 
steam-valves  will  be  shown  when  the  line  on  the  steam-valve 
is  nearer  the  end  of  the  cylinder,  and  the  lead  when  the  line 
is  nearer  the  center  of  the  cylinder  than  the  line  on  the  valve- 
chamber. 

In  adjusting  the  rod  connecting  the  cut-off  or  tripping 
cam  with  the  governor,  the  governor  must  be  at  rest,  and 
the  wrist-plate  at  one  extreme  of  its  throw  or  travel. 

First  adjust  the  rod  connecting  with  the  cut-off  cam  on 
the  opposite  steam-valve  so  that  there  will  be  j$  inch  clear- 
ance between  the  cam  and  the  steel  on  the  tail  of  the  hook. 
Throw  the  wrist-plate  to  the  other  extreme  of  its  travel  and 
adjust  the  cam  for  the  other  steam-valve  in  the  same  manner. 
Now  block  the  governor  up  i^  inch,  which  will  be  its 
average  distance  when  running.  Hook  the  engine  in  and 
turn  it  slowly  in  its  running  direction,  and  mark  the  distance 
the  cross-head  travels  from  its  extreme  position  of  dead- 
center  when  the  cut-off  cam  trips  the  steam-valve.  Continue 
to  turn  the  engine  slowly  past  the  ou,cr  dead-center,  and 
mark  the  distance  of  the  cross-head  from  its  extreme  of  travel 
when  the  steam-valve  drops.  If  the  distance  is  the  same  in 
both  cases,  the  cut-off  is  equal  and  the  adjustment  is  correct. 
If  not,  adjust  one  or  the  other  of  the  .  ods  until  this  is  so. 


3° 
THE  STEAM-ENGINE  INDICATOR. 


The  steam-engine  indicator  is  now  recognized  as  a  highly 
essential  device,  with  which  every  engineer  should  be  familiar. 

The  three  main  objects  for  which  the  indicator  can  be  em- 
ployed are: 

1.  To  serve  as  a  guide  for  setting  the  valves  of  an  engine. 

2.  To  determine  the   indicated  power   developed   by   an 
engine. 

3.  To  determine,  in  connection    with  a  feed- water   test, 
showing  the  actual  amount  of  steam  consumed,  the  economy 
with  which  an  engine  works. 

Among  the  various  indicators  now  on  the  market,  the  Ta- 
bor Indicator  is  recognized  as  the  standard,  and  has  been  se- 
lected to  illustrate  this  article. 

All  indicators  h?.ve  one  essential  plan  of  construction: 
There  is  a  steam-cylinder  and  a  paper  drum. 

The  steam-cylinder  is  designed  to  connect  with  the  inte- 
rior of  the  engine-cylinder  and  receive  steam  whenever  the 
engine  receives  it.  A  piston,  which  is  inclosed,  communi- 
cates motion  to  a  pencil  arranged  to  move  in  a  straight  line; 
the  amount  of  movement  being  limited  by  the  tensio"  of  a 
spiral  spring  against  which  the  piston  acts. 


1\&  paper  drum  is  a  cylindrical  shell  mounted  on  its  axis, 
and  is  made  to  turn  forward  and  backward  by  a  motion  de- 
rived from  the  cross-head  of  the  engine.  A  sheet  of  paper, 
wc\cardy  as  it  is  named,  is  stretched  upon  the  drum,  and  a 
pencil  is  brought  to  bear  upon  it.  In  this  manner,  the 
instrument  traces  upon  the  paper  a  line  termed  the  indicator 
diagram,  which  is  the  object  sought. 

Since  the  motion  of  the  card  is  made  to  coincide  with 
that  of  the  piston  of  the  engine,  and  the  height  to  which  the 
pencil  rises  varies  according  to  variations  in  the  force  of  the 
steam,  the  indicator  diagram  presents  a  record  of  the 
pressure  of  the  steam  in  the  engine  cylinder  at  every  point  of 
the  stroke. 

Sectional  View  of  Standard  Instrument 


THE   METHOD   OF   INDICATING   A   STEAM-ENGINE. 

There  are  two  things  to  be  done  in  making  arrangements  for 
indicating  a  steam-engine.  First,  the  indicator  must  be  at- 
tached to  the  cylinder;  and  second^  means  must  be  provided  for 
giving  motion  to  the  paper  drum.  To  attach  the  indicator,  a 
hole  is  drilled  at  each  end  of  the  cylinder,  and  tapped  for  the 
reception  of  a  half-inch  stenm-pipe(for  the  Tabor  indicator)  to 
which  to  connect  the  indicator  cock.  In  horizontal  engines, 


32 

the  barrel  of  the  cylinder  should  be  selected  in  preference  to 
the  heads,  as  in  the  position  thus  secured  the  indicator  can  be 
themost  easily  operated.  Wherever  attached,  it  is  important 
that  the  pipe  should  communicate  freely  with  the  steam  in 
the  cylinder.  The  hole  should  not  be  located,  for  example, 
in  such  a  position  that  it  is  covered  by  the  piston  rings  at 
the  end  of  the  stroke.  The  pipes  should  be  short  and  free 
from  unnecessary  bends. 

If  a  valve  is  used  beneath  the  cock,  it  should  be  of  the 
straght-way  type.  It  is  not  best  to  connect  the  two  ends  and 
use  a  single  indicator  applied  at  the  center.  .  Errors  are  pro- 
duced by  the  long  connections  and  increased  number  of  bends 
that  this  requires,  especially  at  high  speeds. 

If  but  one  indicator  is  available,  it  maybe  used  alternately, 
first  on  one  end  and  then  on  the  other;  should  it  be  necessary 
to  place  the  indicator  at  the  center,  as  convenience  in  operat- 
ing generally  requires  in  locomotive  work,  the  errors  due  to 
long  connections  may  be  reduced  by  the  employment  of  large 
pipes  and  easy  bends.  For  these  positions,  a  three-way  cock, 
to  which  the  indicator  cock  is  attached,  is  a  useful  appliance. 

In  drilling  and  tapping  new  holes  in  a  cylinder,  care  should 
be  taken  that  the  chips  do  not  enter  it,  unless  they  can  after- 
ward be  removed.  If  no  better  means  can  be  employed, 
steam  may  be  admitted  while  the  work  is  going  on,  and  the 
chips  blown  out  as  fast  as  formed. 

Before  attaching  the  indicator,  the  cock  should  be  opened 
to  the  atmosphere,  and  the  pipes  cleared  of  any  loose  material 
that  may  have  lodged  in  them. 

INDICATOR   DRIVING    RIGGING. 

The  motion  to  be  given  the  paper  drum  is  one  that  coin- 
cides, on  a  reduced  scale,  with  the  motion  of  the  piston  of  the 
engine.  It  may  be  obtained  in  a  variety  of  ways. 

The  active  instrument  here  shown,  is  the  reducing  lever, 
A  C,  which  is  a  strip  of  pine  board  3  or  4  inches  wide,  and 
about  I  %  times  as  long  as  the  stroke  of  the  engine. 

It  is  hung  by  a  screw  or  small  bolt  to  a  wooden  frame  at- 
tached overhead.  At  the  lower  end  a  connecting  rod,  C 
D,  about  one-third  as  long  as  the  stroke,  is  at  one  end  at- 
tached to  the  lever,  and  at  the  other  end  to  a  stud  screwed 
into  the  cross-head,  or  to  an  iron  clamped  to  the  cross-head 
by  one  of  the  nuts  that  adjusts  the  gibs,  or  to  any  part  of 
the  cross-head  that  may  be  conveniently  used.  The  lever  A 
C  should  stand  in  a  vertical  position  when  the  piston  is  in 
the  middle  of  the  stroke.  The  connecting  rod,  C  D,  when 


33 

at  that  point,  should  be  about  as  far  below  a  horizontal  posi* 
tion  as  it  is  above  it  at  either  end  of  the  stroke.  The  cords 
which  drive  the  paper  drums  may  be  attached  to  a  screw  in- 
serted in  the  lever  near  the  point  of  suspension;  but  a  better 
plan  is  to  provide  a  segment,  A  B,  the  center  of  which  coin- 
cides with  the  point  of  suspension,  and  allow  the  cords  t«* 
pass  around  the  circular  edge.  The  distance  from  edge  to 
center  should  bear  the  same  proportion  to  the  length  of  the 


reducing  lever  as  the  desired  length  of  diagram  bears  to  the 
length  of  the  stroke.  On  an  engine  having  a  length  of  48 
inches  the  lever  should  be  72  inches,  and  the  connecting  rod 
16  inches  in  length,  in  which  case,  to  obtain  a  diagram  4 
inches  long,  the  radius  of  the  segment  should  be  6  inches. 
It  is  immaterial  what  the  actual  length  of  the  diagram  is,  but 
4  indies  is  a  length  that  is  usually  satisfactory.  It  maybe 
reduced  to  advantage  to  3  inches  at  very  high  speeds. 


34 

The  cords  should  leave  segment  in  a  line  parallel  with, 
the  axis  of  the  cylinder.  The  pulleys  over  which  they  pass 
should  incline  from  a  vertical  plane  and  point  to  the  incU  • 
cators  wherever  they  may  be  placed. 

If  the  indicators  and  reducing  lever  can  be  placed  so  as  to 
be  in  line  with  each  other,  the  pulleys  may  be  dispensed 
with,  and  the  cords  carried  directly  from  the  segment  to  the 
instrument,  a  longer  arc  being  provided  for  this  purpose. 
The  carrier  pulley  on  each  indicator  should  be  adjusted  so  as 
to  point  in  the  direction  ir.  which  the  cord  is  received. 

THE  ESSENTIAL  'MATURES  OF  THE  INDICATOR  DIAGRAM. 

The  shar^  fj(  the  figure  traced  upon  the  indicator  card 
depends  altogether  upon  the  manner  in  which  the  steam 

f T, 


_AJ 


F.?    *?l 

pressure  acts  in  the  cylinder.  If  the  steam  be  admitted  af  the 
beginning,  and  exhausted  at  the  end,  of  the  stroke,  and  ad- 
mission continue  from  one  end  to  the  other,  the  shape  of  the 
diagram  is  nearly  rectangular.  If  the  admission  continue 
through  only  a  part  of  the  stroke,  the  diagram  assumes  a  shape 
similar  to  that  of  Fig.  No.  I.  These  two  representative 
forms  have,  in  matters  of  detail,  numberless  modifications. 

Fig.  No.  I  has  been  taken  to  illustrate  the  essential  features 
of  the  indicator  diagram,  because  it  exhibits  clearly  all  the 
operations  affected  by  pressure  that  commonly  take  place  in 
the  steam  engine  jylinder. 

This  diagram  shows  that  the  admission  of  steam  commences 
at  A  and  ends  at  D;  the  cut-oif  commences  at  C  and  becomes 
complete  at  D;  expansion  occurs  from  D  to  E;  the  release  or 


35 

exhaust  begins  at  E  and  continues  to  the  point  H  ;  the  com- 
pression of  the  exhaust  steam  commences  at  G  and  ends  at  the 
admission  point,  A. 

The  line  A  B  is  called  the  admission  line  ;  B  C,  the  steam 
lint;  D  E,  the  expansion  line;  F  G,  the  exhaust  or  back 
pressure  line  (or,  in  the  case  of  condensing  engines,  the 
vacuum  line);  H  A,  the  compression  line;  and  J,  I,  the 
atmospheric  line.  The  curve  which  joins  two  adjacent  lines, 
represents  the  action  of  the  steam  when  one  operation 
changes  to  another  and  cannot  properly  be  classed  with  either 
line. 

The  point  of  cut-off,  D,  lies  at  the  end  of  admission;  the 
point  of  release,  E,  at  the  beginning  of  the  exhaust,  the  point 
of  compression,  H,  at  the  end  of  the  exhaust.  The  propor- 
tion of  the  whole  length  of  the  diagram  borne  by  the  distance 
of  the  point  D  from  the  admission  end,  represents  the  pro* 
portion  of  the  stroke  completed  at  the  point  of  cut-off;  so 
also  in  the  case  of  the  point  of  release,  and  in  that  of  com- 
pression for  the  uncompleted  portion  of  the  stroke.  The 
pressures  at  the  points  of  cut-off,  release  and  compression  are 
the  heights  of  these  various  points  above  the  atmospheric  line 
measured  on  the  scale  of  the  spring. 

THE   USES  TO  WHICH  THE  STEAM-ENGINE    INDICATOR   MAY 
BE   APPLIED. 

There  are  three  main  objects  for  the  determination  of 
which  the  indicator  diagram  may  be  employed : 

First.  To  serve  as  a  guide  in  setting  the  valves  of  an 
engine. 

Second.  To  determine  the  indicated  power  developed  by 
an  engine. 

Third.  To  determine,  in  connection  with  a  feed-water 
test  showing  the  actual  amount  of  steam  consumed,  the  econ- 
omy with  which  an  engine  works. 

First.  Figure  No.  I,,  shows  the  general  features  of  a 
well-formed  indicator  diagram,  the  attainment  of  which 
should  be  the  aim  in  setting  the  valves  of  an  engine.  The 
admission  of  steam  is  prompt,  making  the  admission  line  per- 
pendicular to  the  atmospheric  Hne;  the  initial  pressure  is 
fully  maintained  up  to  the  po;:<t  where  the  steam  begins  to  be 
cut  off;  the  somewhat  early  release  secures  a  free  exhaust 
and  a  uniformly  low  back  pressure,  and  the  exhaust  valve 
closes  before  the  return  stroke  is  completed,  providing  for 
compression.  These  are  the  first  requirements  to  be  met  in 
producing  an  economical  engine. 


36 

Derangement  of  the  valve-gearing  is  revealed  in  the  dia- 
gram By  tardy  admission  or  release,  by  low  initial  pressure  or 
high  back  pressure,  or  by  absence  of  compression,  either  one 
of  which  causes  an  increased  consumption  of  steam  for  per- 
forming the  same  amount  of  work. 

The  angular  position  of  the  eccentric  controls  all  the 
movements  of  the  valves,  but  improper  lengths  of  the  con- 
necting rods  which  operate  them,  or  improper  proportions  of 
lap  and  lead,  are  liable  to  produce  some  of  the  faults  we 
mention,  as  w-ill  also  a  wrong  position  of  the  eccentric. 

In  regulating  the  exhaust  of  an  engine,  the  desirability  of 
employing  compression  should  not  be  overlooked.  In  the 
first  place,  it  serves  to  overcome  the  momentum  of  the  recip- 
rocating parts  and  to  reduce  the  strain  upon  the  connections 
caused  by  the  sudden  application  of  the  pressure  at  admis- 
sion. In  the  second  place,  compression  is  desirable  on  the 
ground  of  economy  in  the  consumption  of  steam.  It  fills  the 
wasteful  clearance  spaces  of  the  cylinder  with  exhaust  steam, 
otherwise  requiring  the  expenditure  of  live  steam  from  the 
boiler.  Compression  produces  a  loss  by  the  increased  back 
pressure  which  it  occasions,  but  the  loss  is  more  than  cov- 
ered by  the  gain  resulting  from  the  reduction  of  clearance 
waste.  iHypothetically,  the  greater  the  amount  of  exhaust 
that  is  utilized  by  compression  the  less  the  consumption  of 
steam.  Practically,  it  is  not  advisable  to  compress  above  the 
boiler  pressure.  In  a  non-condensing  automatic  cut-off  engine 
with  3  per  cent,  clearance  working  at  75  Ibs.  boiler  pressure, 
cut  off  at  one-fifth  of  the  stroke,  and  exhausting  under  a  min- 
imum back  pressure,  the  gain  produced  by  compressing  up  to 
boiler  pressure  over  working  under  the  same  conditions  with- 
out compression,  should  be  not  less  than  6  per  cent.  Tn  a 
condensing  engine,  working  under  similar  condition >,  the 
gain  should  be  larger.  It  should  be  larger,  also,  with  an 
earlier  cut-off. 

The  valves  being  in  proper  adjustment,  the  indicator  dia- 
gram shows  whether  the  pipe  and  passages  for  the  admission 
and  exhaust  of  the  steam  are  of  sufficient  size.  In  automatic 
cut-off  engines  the  admission  line  should  be  parallel  with  the 
atmospheric  line,  and  the  initial  pressure  should  not  be  more 
than  3  Ibs.  less  than  the  boiler  pressure.  The  back 
pressure  should  not  in  any  engine  exceed  i  Ib.  when  the  ex- 
haust proceeds  directly  to  the  atmosphere.  Much  can  often 
be  learned  by  applying  the  indicator  to  the  steam  and  exhaust 
pipes,  using  the  same  mechanism  for  driving  the  paper  drum 
as  that  used  when  the  indicator  is  operated  at  the  cylinder. 


37 

Before  making  adjustments  it  pan  engines  that  have  been, 
long  in  usey  the  operator  should  ascertain  whether  a  valve 
which  should  travel  in  a  different  place  has  worn  to  a  shoul- 
der upon  its  seat.  If  changed  under  such  circumstances^ 
loss  from  leakage  may  follow ',  sufficient  in  amount  to  neutral- 
ize the  saving  that  might  otherwise  result.  This  is  a  matter 
of  much  importance. 

Second.  "The  indicator  is  useful  in  determining  the  amount 
of  power  developed  by  an  engine.  The  diagram  reveals  the 
force  of  the  steam  at  every  point  of  the  stroke.  The  power 
is  computed  from  the  average  amount  of  this  force,  which  is 
independent  either  of  the  adjustment  of  the  valves,  the 
form  of  the  diagram  or  of  any  condition  upon  which  economy 
depends.  The  diagram  gives  what  is  termed  the  indicate? 
power  of  an  engine,  which  is  the  power  exerted  by  the  steam. 
The  indicated  power  consists  of  the  net  power  delivered  and, 
in  addition,  that  consumed  in  propelling  the  engine  itself, 
[jln  this  connection  the  indicator  proves  invaluable  for 
measuring  the  amount  of  power  transmitted  to  a  machine  or 
set  of  machines,  which  the  engine  is  employed  to  drive. 
The  process  of  measuring  power  thus  used  consists  in 
indicating  the  engine,  first  with  the  machinery  in  operation, 
and  then  v  \  tJbe  driving-  belt  ow  shaft  thrown  off.  The 
difference  in  the  amount  01  power  developed  in  the  two 
cases  is  the  desired  result.  Tenants,  and  those  who  let 
power,  frequently  employ  the  indicator  for  this  purpose. 

Third  A.  third  use  for  the  indicator  is  in  connection  with 
a  feed-ivatei  \*5t,  in  determining  the  number  of  pounds  of 
steam  consumed  by  ?.n  engine  per  indicated  horse-power  per 
hou/. 

This  quantity  forms  a  treasure  of  the  performance  of  an 
engine,  and  when  compared  with  the  performance  of  the  best 
of  its  class,  shows  the  economy  with  which  the  engine  works. 
The  amount  of  steam  consumed  is  usually  found  by  weigh- 
ing the  feed-water  before  it  is  supplied  to  the  boiler,  the 
steam  being  employed  during  the  tost  for  no  other  purpose 
than  driving  the  engine.  This  requires  the  erection  of  a 
weighing  apparatus,  the  most  satisfactory  form  of  which  con- 
sists of  two  tanks  and  platform  scales.  One  tank  is  placed 
on  the  scales,  and  -these  are  elevated  above  the  second  tank, 
which  is  of  comparatively  large  size.  The  water  is  first 
drawn  into  and  weighed  in  the  first  tank.  It  is  then  emptied 
into  the  second  tank,  which  serves  as  a  reservoir,  and  from 
this  it  is  pumped  into  the  boiler. 

A  simpler  plan  may  be  resorted  to,  w'hich  gives   approxi- 


mate  results.  The  feed-water  is  brought  to  a  high  point  on 
the  glass  water-gauge  and  then  shut  off,  and  a  test  made  by 
observing  the  rate  at  which  the  water  boils  away.  A  fall  of 
six  inches  may  be  allowed  in  nearly  every  case  without  again 
feeding.  The  heights  at  the  beginning  and  the  end  of  the 
test  being  carefully  observed,  the  amount  of  water  evapo- 
rated and  supplied  to  the  engine  is  computed  from  the  cubical 
contents  that  it  occupied  in  the  boilers.  A  test  made  in  this 
manner  can  be  repeated  a  number  of  times,  and  the  results 
averaged  to  insure  greater  accuracy. 

Feed-water  tests,  made  by  measuring  the  water  fed  to  the 
boiler,  are  of  no  value  unless  leakage  of  water  from  the  boiler, 
if  any  exist,  is  allowed  for.  Attention  should  always  be 
given  to  this  point  and  the  rate  of  leakage  determined  by 
observing  the  fall  of  water  in  the  gauge,  when  no  steam  is 
being  drawn  from  the  boiler,  a  constant  pressure  being  main- 
tained. 

A  portion  of  the  feed-water  consumption  of  an  engine  may 
be  found  without  the  aid  of  a  feed-water  test,  by  computation 
from  the  diagram.  Were  it  not  for  the  losses  produced  by 
leakage  and  cylinder  condensation,  to  which  engines  are  sub- 
ject the  whole  amount  of  feed- water  consumed  i merit  be  de- 
termined in  this  manner.  Leakage  of  steam  often  occurs 
and  cylinder  condensation  is  inevitable,  while  the  extent 
to  which  these  losses  act  is  not  revealed  by  any  marked  effect 
produced  upon  the  lines  of  the  diagram.  The  measurement 
of  the  consumption  of  steam  by  diagram,  therefore,  cannot 
be  taken  to  show  actual  performance  without  allowing  a 
margin  for  these  losses.  Much  value,  however,  often  at- 
taches to  these  computations. 

Besides  showing  the  economy  of  an  engine  compared  with 
the  best  of  its  class,  the  indicator,  by  means  of  the  feed -water 
test,  reveals  the  extent  of  the  losses  produced  by  leakage  and 
cylinder  condensation.  These  losses  are  represented  by  that 
part  of  the  feed-water  consumption  which  remains  after  de- 
ducting the  steam  computed  from  the  diagram,  or  steam  ac- 
counted for  by  the  indicator,  as  it  is  termed.  One  of  these 
losses,  condensation,  is  nearly  constant  for  different  engines 
working  under  similar  conditions,  and  an  allowance  may  be 
made  for  its  amount.  The  other,  leakage,  is  variable  in  dif- 
ferent cases,  depending  upon  the  condition  of  the  wearing 
surfaces  of  valves,  piston  and  cylinder.  The  fact  of  the  pres- 
ence of  the  latter  may  be  detected  by  a  trial  under  boiler 
pressure  with  engine  at  rest,  the  leakage  being  revealed  by 
escape  at  the  indicator  cock  or  exhaust  pipe.  The  amount  of 


39 

this  leakage  may  be  found  by  computing  that  part  of  the  loss 
not  covered  by  condensation.  In  other  words,  in  the  case  of 
leaking  engines,  when  the  indicator  and  feed-water  test  show 
.that  there  is  more  loss  than  is  produced  in  good  practice  by 
condensation,  the  excess  represents  the  probable  amount  of 
loss  by  leakage.  A  valuable  use  for  the  indicator  is  thus 
found  in  connection  with  the  feed-water  test.  To  make  it 
available  in  practice,  Tables  Nos.  I,  2.  and  3  are  appended, 
showing  the  percentages  of  loss  that,  occui  from  cylinder 
condensation.  The  quantities  in  Table  No.  I  apply  to  that 
type  of  simple  engine  commonly  used,  that  is,  to  unjacketed 
engines  having  cylinders  exceeding  twenty  inches  in  diameter; 
the  quantities  in  Table  No.  2  apply  to  compound  engines  of 
the  best  class  having  steam  jacketed  cylinders;  and  the  quan- 
tities in  Table  No.  3  apply  to  triple  expansion  engines  of  the 
best  class,  also  having  steam  jacketed  cylinders,  all  supplied 
with  dry  but  not  superheated  steam. 

TABLE   NO.    I. 

Percentage  of  loss  by  cylinder  condensation   taken  at  cut-off 
in  simple  engines. 


Percentage     of    Feed- 

Percentage     of     Feed- 

Percentage    of    stroke 
completed  at  cut-off. 

water      consumption 
accounted  for  by  the 

water       consumption 
due  to   cylinder   con- 

indicator diagram. 

densation. 

5 

P 

42 

IO 

66 

34 

15 

7i 

29 

20 

74 

26 

3° 

78 

22 

40 

82 

18 

50 

86 

14 

TABLE    NO.    2. 

Percentage  of  loss  by  cylinder  condensation  taken  at  cut-off 
in  the  H.  P.  cylinder  in  compound  engines. 


Percentage    of    Feed- 

Percentage     of     Feed- 

Percentage    of    stroke 
completed  at  cut-oft". 

water     consumption 
accounted  for  hy  the 

water      consumption 
due   to  cylinder  con- 

indicator diagram. 

densation. 

10 

74 

26 

'5 

76 

24 

20 

78 

22 

3° 

82 

18 

40 

85 

15 

50 

88 

12 

40 

MANNER  OF   TAKING   DIAGRAMS 

To  take  a  diagram,  a  blank  card  is  stretched  smoothly  upon 
the  paper  drum,  the  ends  being  held  by  the  spring  clips. 
The  driving  cord  is  attached  and  so  adjusted  that  the  motion 
of  the  drum'  is  central.  The  cock  is  opened  to  admit  steam 
to  the  indicator  till  the  parts  have  become  heated,  which 
will  be  after  a  half-dozen  revolutions.  On  being  shut  off, 
the  pencil  or  marking  point  is  brought  into  contact  with  the 
paper,  the  stop  screw  is  adjusted,  and  a  fine  clear  line  traced 
upon  the  card.  This  is  the  atmospheric  line.  The  cock  is 
then  opened,  and  after  two  or  three  revolutions  the  pencil  is 
again  applied  and  the  diagram  taken.  If  it  is  desired  to  as- 
certain the  condition  of  the  valve  adjustment,  the  pencil 
needs  to  be  applied  only  while  the  engine  is  making  one  rev- 
olution. But  to  determine  power,  it  should  be  applied  a 
longer  time,  so  as  to  obtain  a  number  of  diagrams  superposed 
on  the  same  card.  The  fluctuations  in  the  admission  of 
steam,  produced  by  governors  which  do  not  regulate  closely, 
are  so  common,  that  this  course  should  always  be  followed  to 
obtain  average  results.  The  diagram  having  been  traced, 
and  the  cock  shut,  the  pencil  should  be  applied  lightly  to  the 
paper  to  see  that  the  position  of  the  atmospheric  line  re- 
mains the  same.  If  a  new  line  is  traced,  it  is  evidence  of 
error  or  derangement,  and  the  operations  should  be  re- 
peated on  a  new  card. 

It  is  well  to  mark  upon  every  card  the  date,  time  of  day, 
and  end  of  the  cylinder  from  which  it  was  taken.  In  ad- 
justing the  valves,  the  boiler  pressure  should  be  observed, 
and  the  changes  that  are  made  before  taking  a  diagram  .noted 
on  the  card  for  reference.  If  a  series  of  diagrams  is  being 
obtained  for  power,  they  should  be  numbered  in  order,  and 
the  number  of  revolutions  per  minute  noted,  either  upon 
every  card,  or,  if  the  speed  is  nearly  constant,  upon  every 
other  one. 

If  tests  are  to  be  made  for  power  used  by  machines  or 
tenants,  a  number  of  diagrams  should  be  obtained  under  each 
condition  and  the  results  averaged.  It  is  well,  in  these  cases, 
to  mark  each  card  of  a  set  by  some  letter  of  the  alphabet, 
and  on  the  first  of  the  set  specify  the  machines  in  operation 
at  the  time. 

SPECIAL     INSTRUCTIONS. 

When  accurate  work  is  desired,  too  much  care  cannot  be 
exercised  in  indicating  an  engine,  and  a  further  consideration 


41 

of  some  of  the  points  to  be  observed  will  aid   the  engineer 
in  realizing  their  importance. 

Short  steam  connections  from  the  cylinder  to  the  indicator 
are  desirable  in  all  cases,  and  absolutely  necessary  with  high 
speed  engines.  Avoid  all  turns,  if  possible. 

Lubrication  of  the  indicator  piston. — The  best  cylinder 
oil  only  should  be  used  for  this  purpose.  The  piston  should 
be  removed,  and  the  cylinder  and  piston  cleaned  and  oiled 
every  half-dozen  diagrams.  The  oil  contained  in  the  steam 
is  not  sufficient  in  any  case  to  lubricate  this  piston.  Alack 
of  lubrication  will  make  a  jumping  acti  on  in  the  movement 
of  the  pencil,  showing  a  series  of  steps,  not  waves,  on  the 
diagram. 

Spring  to  be  used. — On  slow  speed  engines  the  lightest 
spring  that  will  accommodate  the  pressure  is  best,  but  in 
high  speed  engines  a  heavier  spring  is  necessary  for  the  same 
pressure,  in  order  to  restrict  the  movement  of  the  pencil  bar 
and  connections,  and  prevent  their  inertia  from  distorting  the 
diagram.  A  waving  line  is  the  result  of  too  great  a  move- 
ment of  these  parts. 

The  tension  of  the  spring  in  paper  drum  should  in  all 
cases  be  just  sufficient  to  keep  the  cord  tight;  but  this  means 
that  a  greater  tension  must  be  used  with  high  than  with  low 
speeds,  to  prevent  the  inertia  of  the  drum  over-winding  itself 
and  distorting  the  diagram;  breakage  of  the  cord  also  fre- 
quently results  from  this  cause. 

Keeping  the  cord  leading  from  engine  under  tension. — , 
This  is  of  no  importance  with  slow  running  engines, 
but  when  indicating  high  speed  engines  it  is  desirable 
that  this  cord  should  always  be  kept  taut,  whether  the 
paper  drum  is  running  or  not.  A  good  plan  is  to  fasten 
one  end  of  a  rubber  band  to  the  driving  cord  four  or  five 
inches  from  the  end  and  attach  the  other  end  of  the  band  to 
the  indicator  just  below  the  carrier  pulley,  so  that  it  always 
keeps  a  tension  on  the  driving  cord;  then  make  a  loop  in  the 
end  of  this  cord  for  hooking  on  the  indicator,  and  the  loose 
end  admits  of  readily  connecting  and  disconnecting  without 
allowing  the  driving  cord  to  become  slack  for  an  instant. 

Length  of  the  diagrams.  — With  slow  speeds  a  length  of  4 
in.  to  4^  in.  will  show  well  proportioned  diagrams,  but  as 
the  speeds  increase  the  diagrams  must  be  shortened  to  avoid 
the  effects  of  the  inertia  of  the  paper  drum;  and  at  very  high 
speeds  an  instrument  with  the  small  paper  drum  should  be 
used.  Diagrams  at  very  high  speeds  should  not  exceed  2  hif 
in  length,  and  frequently  i^£  in.  will  give  better  results. 


42 

The  pressure  of  the  p'eri'cil  on  the  paper  should  be  just 
sufficient  to  make  a  legible  mark,  and  no  more;  a  greater 
pressure  only  creates  friction,  and  consequent^  inaccuracy  in 
the  diagram. 

Water  in  the  indicator  will  make  a  curious  but  not  a  use- 
ful diagram,  and  therefore  care  should  be  exercised  that  the 
indicator  is  thoroughly  heated  up  before  a  diagram  is  taken. 
Also,  if  much  water  is  entrained  in  the  steam,  it  will  be  nec- 
essary to  leave  the  cylinder  cocks  slightly  open  while  taking 
diagrams,  as  otherwise  a  distorted  diagram  is  almost  a  cer- 
tainty. 

When  taking  diagrams  from  steam-engines,  the  height  of 
the  barometer  or  pressure  of  the  atmosphere  should  always 
be  carefully  noted.  This  is  necessary  when  the  economy  of 
the  engines  are  to  be  considered,  and  it  is  desirable  in  all 
cases  to  know  how  much  the  exhaust  pressure  is  above  zero. 
Even  at  the  sea  level  the  pressure  is  constantly  changing, 
and  there  are  many  engines  working  at  places  far  above  the 
sea  level  where  the  atmospheric  pressure  is  always  less,  and 
in  some  cases  very  much  less,  than  14.7  Ibs.  per  square  inch, 
or  29.9  in.  of  murcury.  Care  should  therefore  be  exercised 
in  this  respect,  as  there  is  a  tendency  among  engineers  to 
ignore  this  fact. 

All  gauges  in  ordinary  use  indicate  pressures  above  the 
atmosphere;  if  pressure  gauges,  or  if  vacuum  gauges  the 
amount  below  atmospheric  pressure;  but  neither  kind  show 
the  pressure  above  zero,  or  total  pressure,  and  to  arrive  at 
this,  the  pressure  of  the  atmosphere  must  be  added  to  the  gauge 
pressure  in  the  first  case,  or  the  amount  of  vacuum  sub- 
tracted from  the  atmospheric  pressure  in  the  second. 

THE    METHOD     OF    COMPUTING  THE     HORSE-POWER   OF   AN 
ENGINE   FROM   THE  INDICTOR   DIAGRAM. 

The  work  done  by  the  steam  in  the  cylinder  of  an  engine 
is  measured  by  the  product  of  the  force  exerted  on  the 
piston,  into  the  distance  through  which  the  piston  moves, 
and  is  usually  expressed  by  the  term  foot-pounds.  If,  for 
example,  a  force  of  33  Ibs.  per  square  inch  on  a  piston  having 
an  area  of  100  square  inches  is  employed  to  drive  the  piston 
100  times  over  a  stroke  of  4  feet,  the  work  done  by  the  steam 
amounts  to  1,320,000  ft.  Ibs.  The  amount  of  horse-power 
which  the  steam  develops  is  the  foot-pounds  of  work  done  in 
a  minute  divided  by  33,000.  In  the  example  given,  the 
horse-power  developed  when  100  strokes  are  made  per 
minute  i.s  1,320,000  divided  by  33,000  or  40  H.  P. 


The  force  exerted  upon  the  piston  is  given  by  tlieindicaic- 
diagram,  but  as  it  varies  in  amount  at  different  points  of  the 
stroke,  it  is  necessary  to  determine  the  equivalent  force 
which,  acting  constantly,  would  produce  the  same  result. 
This  is  done  by  computing  from  the  diagram  what  is  termed 
the  mean  effective  pressure.  The  product  of  the  mean 
effective  pressure,  expressed  in  pounds  per  square  inch;  the 
area  of  the  cylinder,  expressed  in  square  inches;  the  length  of 
the  stroke,  expressed  in  feet;  and  the  number  of  strokes  per 
minute,  which  is  twice  the  number  of  revolutions  per  minute, 
gives  the  number  of  foot-pounds  of  work  performed  per 


-rrrf 


H 


X. 

m 

minute.     This  result,  divided  by  33,000  gives  the  amount  of 
horse-power  developed. 

To  compute  from  the  diagram  the  mean  effective  pressure, 
two  lines  are  drawn  perpendicular  to  the  atmospheric  line, 
one  at  each  end  of  the  diagram,  and  the  intermediate 
space  divided  into  10  equal  parts,  with  a  perpen- 
dicular at  each  point  of  division.  A  ready  method 
of  performing  the  division  is  to  lay  upon  the  diagram 
a  scale  of  10  equal  parts,  the  total  length  of  which 
is  a  small  amount  in  excess  of  the  length  of  the 
diagram.  It  is  so  placed  in  a  diagonal  position  that  the 
extreme  points  on  the  scale  lie  upon  the  two  outside  perpen- 
diculars. The  desired  points  may  then  be  dotted  with  a 
sharp  pencil  opposite  the  intermediate  divisions  on  the 
Scale.  The  points  where  the  lines  of  division  cross  the 


44 

diagram  should  be  dotted;  and  in  locating  these  points  they 
should  be  so  placed  that  the  area  of  the  figure  inclosed  by 
straight  lines  joining  them  is  exactly  equal  to  the  area  in- 
closed by  the  curved  line  of  the  diagram.  The  proper  loca- 
tions can  be  readily  determined  by  the  eye. 

Figure  No.  2  shows  the  extreme  perpendiculars  A  B  and 
C  D,  the  intermediate  lines  of  cliv  sion,  the  points  of  inter- 
section, and  those  points  which  require  special  location,  as, 
for_example,  the  one  at  E,  which  is  so  placed  that  the  area 
inclosed  by  the  straight  lines,  E  E  and  E  G,  is  equal  to  that 
inclosed  by  the  diagram  from  F  to  G. 

The  determination  of  the  mean  effective  pressure  consists 
now  of  finding  the  average  length  of  the  various  perpendicu- 
lar lines  included  between  the  points  of  intersection,  meas- 
ured on  the  scale  of  the  spring.  This  may  be  done  by  meas- 
uring each  line  with  the  scale  and  averaging  the  results.  'A 
better  and  quicker  method  is  to  employ  a  strip  of  paper,  one 
of  the  cards  upon  which  the  diagram  is  traced,  if  desired,  and 
mark  one  after  another  the  various  distances  on  its  edge, 
making  thereby  a  mechanical  addition,  and  requiring  only  a 
final  measurement.^  The  proper  course  to  pursue  is  to  lay  the 
edge  of  the  paper  on  the  first  line  and  mark  off  the  distance, 
A  H,  starting  from  the  end  of  the  paper.  Transfer  the  edge  of 
the  paper  to  the  last  line,  and  add  to  the  first  measurement  the 
distance,  I  D.  Mark  off  from  the  end  of  the  paper  one-half 
of  the  sum  of  these  two  distances,  and  from  the  middle  point 
continue  the  addition  for  the  intermediate  nine  divisions. 
When  all  have  been  marked  measure  with  the  scale  of  the 
spring,  from  the  end  of  the  paper  to  the  end  of  the  last 
addition,  and  divide  the  result  by  ten.  This  gives  the  mean 
effective  pressure.  It  is  essential  that  one-half  the  sum  of 
the  first  and  last  distances  be  taken,  and  the  sum  of  this 
together  with  the  intermediate  nine  be  divided  by  ten.  An 
erroneous  result  is  obtained  by  taking  the  sum  of  the  whole 
and  dividing  by  eleven. 

The  engineer  who  is  so  fortunate  as  to  possess  the  knowl- 
edge necessary  to  operate  an  Indicator  will  find  that  his  posi- 
tion is  not  only  more  secure  to  him,  but  his  employers  will 
be  very  apt  to  show  their  appreciation  in  a  pecuniary  manner. 

The  use  of  the  Indicator  as  a  detective,  detecting  errors, 
misadjustments,  waste  and  lost  motion  in  an  engine  makes  it 
a  most  necessary  adjunct  to  the  engine-room.  'This  fact  is 
becoming  "^ore  patent  every  day. 


45 
STEAM-BOILERS. 

All  boilers  are  divided  into  three  different  parts,  viz.,  fire- 
surface,  water-space  and  steam-room.  Each  part  or  division 
has  a  distinct  and  separate  duty  to  perform.  The  fire-surface 
includes  the  furnace  and  combustion  chamber,  flues  and 
tubes;  the  water-space  is  that  part  occupied  by  the  water;  and 
the  steam-room  is  the  reservoir  which  holds  and  supplies  the 
steam  necessary  to  run  the  engine. 

All  steam-boilers  are  either  internally  or  externally  tired. 
Locomotive,  marine  and  portable  boilers  are  internally  fired 
because  the  fuel  is  burned  in  an  iron  furnace  surrounded  with 
a  water-jacket  or  water-leg.  Cylinder-flue,  double-deck,  tub- 
ulous  and  sectional  boilers  are  externally  fired,  because  the 
fuel  is  burned  in  a  brick  furnace  lined  with  fire-brick. 

A  perfect  steam-boiler  should  be  made  of  the  best  material 
sanctioned  by  use,  and  should  be  simple  in  construction. 
It  should  have  a  constant  and  thorough  circulation  of  water 
throughout  the  boiler,  so  as  to  maintain  all  parts  at  one  tem- 
perature. 

It  should  be  provided  with  a  mud-drum  to  receive  all  im- 
purities deposited  from  the  water,  and  the  mud-drum  should 
be  in  a  place  removed  from  the  action  of  the  fire. 

It  should  have  a  combustion  chamber  so  arranged  that  the 
combustion  of  the  gases  commenced  in  the  furnace  may  be 
completed  before  the  escape  to  the  chimney. 

All  parts  should  be  readily  accessible  for  cleaning  and 
repairs. 

The  boiler  should  have  ample  water  surface  for  the  dis- 
engagement of  the  steam  from  the  water  in  order  to  prevent 
foaming.  It  should  have  a  large  excess  of  strength  over 
any  legitimate  strain.  It  should  be  proportioned  for  the 
work  to  be  done. 

It  should  have  the  very  best  gauges,  safety-valves,  fusible 
plugs,  and  other  fixtures. 

A  water-tube  boiler  should  have  from  10  to  12  square  feet  of 
heating  surface  for  one  horse-power;  a  ttibular  boiler  14  to 
1 8  square  feet  of  heating  surface  for  one  horse-power;  a 
flue-boiler  8  to  12  square  feet  of  heating  surface  for  one  horse- 
power ;  a  plain  cylinder  boiler  should  have  from  6  to  10 
square  feet  of  heating  surface  for  one  horse-power;  ^.locomotive 
boiler  should  have  from  12  to  16  square  feet  of  heating  surface 
for  one  horse-power;  a  vertical  boiler  should  have  from  15  to 
20  square  feet  of  heating  surface  for  one  horse-power. 

The  following  table  gives  an  approximate  list  of  square  feet 
of  heating  surface  per  H.  P.  in  different  styles  of  boilers;  the 


46 

rate  of  combustion  of  coal  per  hour,  per  square  foot  of  grate 
surface,  required  for  that  rating;  the  relative  economy,  and 
the  rapidity  of  steaming: 


TVI-E  OF  BOILER. 

Sq.    ft.   for 
one  H.  P. 

Coal  for 
each  sq.  ft. 

Relative 
Economy. 

Relative 
rapidity  of 
Steaming. 

Water  tube  ". 

IO  to  12 

.3 

I  .OO 

1.  00 

Tubular  

14  to  18 

.25 

.91 

-5° 

Flue  

8  to  12 

•4 

•79 

•25 

Plain  cylinder  

6  to  10 

.5 

.69 

.20 

Locomotive  

12  to  16 

-275 

.85 

.55 

Vertical  tubular. 

15  to  20 

25 

.80 

.60 

to 


HORSE-POWER. 

Strictly  speaking  there  is  no  such  thing  as  "  horse-power  " 

a  steam  boiler;  it  is  a  measure  applicable  only  to  dynamic 
effect.  But,  as  boilers  are  necessary  to  drive  steam-engines, 
the  same  measure  applied  to  steam-engines  has  come  to  be 
universally  applied  to  the  boiler.  The  standard,  as  fixed  by 
Watt,  was  one  cubic  foot  of  water  evaporated  per  hour  from 
212°  for  each  horse-power.  This  was,  at  that  time, 
the  requirement  of  the  best  engine  in  use.  Since  Watt's 
time,  however,  this  requirement  has  been  reduced  until 
engines  requiring  but  one-half  or  one-quarter  a  cuWc  foot  of 
water  per  hour,  are  in  daily  use.  However,  even  though 
the  Centennial  Exposition  in  Philadelphia  adopted  as  a 
standard  for  tests  of  boilers  30  founds  water  per  hour,  eva- 
porated at  70  pounds  pressure,  from  100°  for  each  horse- 
power, the  general  rule,  in  estimating  horse-power  of  boilers 
is  based  on  its  evaporating  one  cubic  foot  of  water  per  horse- 
power per  hour.  A  cubic  foot  of  water  weighs  62^  pounds. 

Estimating  horse-power  of  boilers.  —  One  cubic  foot,  or 
62^  pounds,  or  6.23  gallons  of  water  evaporated  per  hour, 
is  equivalent  to  one  horse-power.  That  is,  a  boiler  that  will 
evaporate  ten  cubic  feet  of  water,  or  625  pounds  of  water,  or 
62  1/3  gallons  of  water  per  hour,  is  a  boiler  of  lo  horse-power. 

An  easy  approximate  rule  for  estimating  the  horse-power  of 
a  boiler  off-hand  (if  the  boiler  is  a  cylinder  or  flue  boiler)  is 
to  multiply  the  length  of  the  boiler  by  the  diameter,  in  feet, 
and  divide  by  6;  the  quotient  will  be  the  nominal  horse- 
power. •£  Another  rule,—  Multiply  the  heating  surface  in 
square  yards  by  the  fire  grate  surface  in  square  feet;  the 
square  root  of  the  product  will  be  the  nominal  horse-power. 


47 

In  estimating  the  heating  surface  of  a  boiler,  a  vertical  or 
upright  surface  has  only  one-half  the  evaporative  value  of  a 
horizontal  surface  above  the  flame.  That  is,  the  sides  of  a 
locomotive  fire-box  are  only  half  as  effective  per  square  foot 
as  the  flat  top  of  the  box.  In  flues  and  tubes,  the  effective 
surface,  measured  on  the  circumference,  is  i%  times  the 
diameter. 

To  find  the  fire-grate  surface  of  fine  boilers. — Square  the 
nominal  horse-power,  and  divide  it  by  the  heating  surface  in 
square  yards ;  the  quotient  will  be  the  fire-grate  surface  in 
square  feet — or,  one  square  foot  of  fire-grate  surface  per 
nominal  horse-power. 

To  find  the  hea'ing  surface  of  a  flue-boiler. — Square  the 
nominal  horse-power  and  divide  that  by  the  fire-grate  surface 
in  square  feet;  the  quotient  will  be  the  heating  surface  in 
square  yards. 

Capacity  of  Boiler  Jlue.  — One  cubic  yard  of  boiler  capa- 
city for  each  nominal  horse-power.  Steam  room  should  be 
about  eight  times  the  contents  of  the  cylinder  of  the  engine 
supplied  with  steam  by  the  boiler. 

To  find  the  nominal  horse-power  of  a  locomotive  boiler.-*  - 
Square  ihe  area  of  the  heating  surface  in  square  feet,  and 
divide  by  the  area  of  the  fire  grate  in  square  feet;  multiply 
the  quotient  by  .0022;  the  product  will  be  the  nominal  horse- 
power. 

To  find  the  area  of  the  heating  surface  of  a  locomotive 
boiler. — Multiply  the  nominal  horse-power  by  the  area  of 
the  grate  in  sqtiare  feet;  extract  the  cube  root  of  the  product, 
and  multiply  the  root  by  21.2,  the  product  is  the  area  of  the 
heating  surface  in  square  feet. 

To  find  the  area  of  the  fire-grate  surface  of  a  locomotive 
boiler. — Square  the  area  of  the  heating  surface  in  square 
feet,  divide  it  by  the  number  of  nominal  horse-power,  or  the 
cubic  feet  of  water  evaporated  per  hour.  The  quotient 
multiplied  by  .0022  will  be  the  area  of  the  fire-grate  surface  in 
square  feet. 

Or,  divide  the  area  of  the  heating  surface  in  square  feet  by 
65,  the  quotient  will  be  the  area  of  the  fire-grate  in  square 
feet,  nearly. 

Tubular  or  marine  boilers. — Each  nominal  horse-power 
requires  the  evaporation  of  one  cubic  foot  of  water  per  hour; 
12  square  feet  of  heating  surface,  only  three-fourths  of  the 
whole  tube-surface  being  taken  as  effective;  and  30  square 
inches  of  fire-grate  per  nominal  horse-power.  The  sectional 
area  of  the  tubes  to  be  about  one-sixth  of  the  fire-grate. 


49 

General  rule  for  all  classes  of  boilers. — Twelve  square  reet 
of  heating  surface  and  three-fourths  square  foot  of  fire-grate 
per  nominal  horse-power,  are  very  good  proportions. 

TEMPERATURE  INDICATED  BY  THE  COLOR  OF  THE  FIRE. 

To  determine  the  temperature  of  a  furnace  fire  from  the 
color  of  the  flame: 

Faint  red 960°  F. 

Bright  red 1,300°  F. 

Cherry  red 1, 600°  F. 

Dull  orange 2,000°  F. 

Bright  orange 2, 100°  F. 

White  heat.. 2,400°  F. 

Brilliant  white  heat 2,700°  F. 

RULES  FOR  SAFETY-VALVES. 

(See  also  f  age  82.} 

I. — To  find  the  distance  from  the  fulcrum  at  which  a  given 
weight  is  to  be  placed  on  the  lever,  in  order  to  balance  a  given 
pressure  in  the  boiler. — Multiply  the  steam  presstire  on  the 
whole  area  of  the  safety-valve  by  the  distance  of  the  center  of 
the  valve  from  the  center  of  the  fulcrum.  Multiply  the  dead 
weight  of  the  lever  and  the  valve  by  half  the  length  of  the 
lever,  subtract  this  product  from  the  first  product,  and  divide 
the  remainder  by  the  given  weight,  supposed  to  be  a  cast-iron 
ball.  ^The  quotient  is  the  required  distance  of  the  weight 
from  the  fulcrum  in  inches.  It  is  necessary,  in  order  to  find 
the  steam  pressure  on  the  valve,  to  multiply  the  area  of  the 
valve-seat  in  inches  by  the  pounds  pressure  per  square  inch. 

Suppose  that  the  entire  pressure  of  steam  on  the  valve  is  24 
pounds,  that  the  center  of  the  valve  is  2  inches  from  the  cen- 
ter of  the  fulcrum,  and  that  the  weight  of  the  ball  is  3  pounds 
— the  first  product  is  24  X  2  =  48 ;  the  length  of  the  lever  is 
16  inches,  and  the  united  weight  of  the  lever  and  valve  is 
4  pounds;  then  the  second  product  is  (16—2)  8  X  4  =  32. 
Then  48  —  32  =  16,  and  1 6  ~-  3  =5^  inches,  the  required 
distance  of  the  center  of  the  ball  from  the  center  of  the 
fulcrum. 

2.  To  find  the  weight  of  the  ball  to  hang  onto  a  given 
length  of  lever,  in  order  that  the  steam  may  blow  off  at  a, 
g&ven  pressure. — Multiply  the  whole  pressure  on  the  valve 
by  its  distance  from  the  fulcrum  (center  to  center) ;  from  this 
product  subtract  the  product  of  the  weight  of  the  lever  and 
valve,  multiplied  by  one-half  of  the  length  of  the  lever; 
then  divide  the  remainder  by  the  whole  length  of  the  lever. 
The  quotient  is  the  weight  of  the  ball  in  pounds. 


For  example — The  pressure  in  the  boiler  is  60  pounds  per 
square  inch  on  the  valve,  the  center  of  the  valve  is  2  inches 
from  the  fulcrum,  the  weight  of  the  valve  and  lever  is  lo 
pounds,  and  the  length  of  the  lever  is  14  inches. 

Suppose  the  opening  in  the  boiler  to  be  2  inches  in  diame- 
ter, then  2  squared  =  4  :  and  4  multiplied  by  .7854  =  3. 1416 
square  inches,  the  area  of  the  valve.  The  whole  pressure  on 
the  valve  is  60  pounds  3.1416  =  188.496  pounds.  The 
distance  of  the  center  of  the  valve  from  the  fulcrum  is  2 
inches,  and  188.496  multiplied  by  2=  376.992.  From  this 
product,  subtract  the  product  of  the  weight  of  the  valve  and 
lever  (10  pounds)  by  the  half-length  of  lever,  7  inches  (total 
length  of  lever  14  inches)  or  lo  7  =  70.  Then  376.992  — 
70  =  306. 992;  and  306. 922  divided  by  the  length  of  the  lever, 
or  14  inches,  equals  21. 928  pounds,  the  required  length  of  ball. 

To  find  the  pressure  on  the  valve. — Multiply  the  weight  of 
*ke  ball  by  the  length  of  the  lever;  to  this  product  add  the 
/•tf-ocruct  of  trie  weight  of  the  lever  and  valve  by  the  half- 
length  of  lever,  and  divide  the  sum  by  the  distance  of  the 
valve  from  the  fulcrum.  The  quotient  is  the  pressure  on  the 
valve  in  pounds.  Divide  this  quotient  by  the  area  of  the 
valve  in  square  inches,  and  the  quotient  will  give  the  blow-off 
pressure. 

Suppose  the  ball  weighs  21.928  pounds,  the  length  of  the 
lever  14  inches,  the  weight  of  the  lever  and  valve  10  pounds, 
the  distance  of  the  valve  from  the  fulcrum  2  inches,  then 
(21.928  X  14  =  306.992)  +  10  X  7  =  70  =  376.992;  and 
376.992  -:-  2  =  188.496  pounds,  the  whole  pressure  on  the 
valve.  This  pressure  divided  by  3. 141 6  square  inches,  the 
area  of  the  2"  valve  =60  pounds,  the  pressure  per  square 
inch  on  the  boiler. 

SAFETY   VALVE   CAPACITY. 

A  safety  valve  should  be  capable  of  discharging  all  the 
steam  that  the  boiler  can  make  with  all  other  outlets  shut. 
The  United  States  regulations  call  for  one-half  square  inch 
valve  area  for  each  square  foot  of  grates;  but  where  the  lift 
will  give  an  effective  area  of  one-half  that  due  to  the  diameter 
of  the  valve,  one-fourth  square  inch  valve  area  per  square 
foot  of  grate  will  answer.  They  give  the  following  diame- 
ters: 


Area  of  Grate,  Square  Feet. 

Diameter  of  Valve,    Inches. 

Common  Valve. 

Improved  Valve. 

1# 

2 

2/8 
2X 
2/8 
2'X 

2,¥ 

I« 

I 

33X 
3# 
4 

4X 

4/8 

4^ 
4^ 
4^ 

n 

i 
i 
ift 

1/8 
j# 
1/8 
I# 
1/8 
I* 

:*i# 

i/s 

2 
2 
2>£ 
2X 
2X 
2/8 
2/8 

^ 

,_ 

8  

o.  . 

10  

12  .  . 

14.             .  .                ... 

16     ,  

18 

20  

22    

24    

26  

28            

3O 

^2                               

34 

36  

CARE  OF  BOILERS. 

1.  Safety  Valves. — Great  care  should  be  exercised  to  see 
that  these   valves  are  ample    in  size  and  in  working  order. 
(See  rules  for  Safety  Valves,  page  82.}     Overloading  or  neg- 
lect  frequently  lead  to  the  most  disastrous    results.     Safety- 
valves  should  be   tried  at  least   once  a  day    to   see   if  they 
will  act  properly. 

2.  Pressure    Gauge. — The   steam-gauge   should  stand  at 
zero  when  the  pressure  is  off,  and  it  should  show  same  press- 
ure as  the  safety  valve  when  the  latter  is  blowing  off.     If 
not,  then  one  is  wrong,  and  the  gauge  should  be  tested  by 
one  known  to  be  correct. 

3.  Water  Level. — The  first  duty  of  an  engineer   before 
starting  is  to  see  that  the  water  is  at  the  proper  height.     Do 
not  rely  on  glass  gauges,  floats  or  water  alarms,  but  try  the 
gauge-cocks. 

4.  Gauge-Cocks  and  Water-Ganges. — Both  must  be  kept 
clean.     Water-gauges  should  be  blown  out  frequently,  and 
the  glasses  and  passages  to  gauge  kept  clean. 

5.  Feed-Pumpor  Injector. — ^hese  should  be  kept   in  per- 


52 

feet  order,  and  of  ample  size.  No  make  of  pump  can  be 
expected  to  be  continuously  reliable  without  regular  and  care- 
ful attention.  It  is  always  safe  to  have  two  means  of  feeding 
the  boiler.  Check-valves  and  self-acting  feed-valves  should 
be  frequently  examined  and  cleaned.  Satisfy  yourself  that  the 
valve  is  acting  when  the  feed-pump  is  at  work. 

6.  Low  Water. — In  case  of  low  water  immediately  cover 
the  fire  with  ashes  (wet  if  possible)  or  any  earth  that   may 
be  at  hand.     If  nothing  else  is  handy  use  fresh  coal.     Draw- 
fires  as  soon  as  it  can  be  done  without  increasing  the   heat. 
Neither  turn  on  the  feed^  start  or  stop  engine^  or  lift  safety- 
valve  iintil  fires  are  out  and  the  boiler  cooled  down. 

7.  Blister  and  Cracks. — These  are  liable  to  occur  in  the 
best   plate   iron  or  steel.     When   first  indications  appears, 
there  must  be  no  delay  in  having  it  examined  and  carefully 
cared  for. 

8.  Fusible  Plugs. — When  used,  must  be  examined  when 
the  boiler  is  cleaned,  and  carefully  scraped  clean    on  both 
water  and  fire  sides,  or  they  are  liable  not  to  act. 

9.  Firing. — Charge  evenly  and   regularly,  a  little   at  a 
time       Moderately  thick  fires  are  most  economical,  but  thin 
firing  must  be  used  when  draught  is  poor.      Take  care  to 
keep  the  grates  evenly  covered,  and  allow  no  air-holes  in  the 
fire.      Be  especially  careful  to  lay  the    coal   along  the  sides 
and  in  the  corners.     All  lumps  should  be  broken  into   the 
size  of  a  man's  fist.     With  bituminous  coal,  a  "  coking  fire" 
(that  is,  firing  in  front,  and  then  shoving  the  coal  back  when 
it  is  coked),  gives   the   best   result.     Do  not   "  clean  "  fires 
oftener  than  necessary.     The  cleaning  of  the  fire  is  best  done, 
in  ordinary  working,  by  a  "  rake,"  or  other  tool,  working  on 
the  under  side  of  the  grate,  and  not  by  a  "  slice-bar,"  driven 
into  the  mass  of  fuel  above  the  grates. 

10.  Cleaning. — All  heating  surfaces  must  oe  kept  clean, 
outside  and  in,  or  there  will  be  serious  waste  of  fuel.     The 
frequency  of  cleaning  will  depend  on  the  nature  of  the  fuel 
and  water.     As  a  rule  never  allow  over  one-sixteenth  inch 
scales  or  soot  to  collect  on  surfaces  between  cleanings.     Hand 
holes  should  be  frequently  removed  and  surfaces  examined, 
particularly  in  case  of  a  new  boiler,  until  proper  intervals 
between   cleanings    have   been    established    by   experience. 
Examine  mud-drums  and  remove  sediment  therefrom. 

1 1.  Hot  Water  Feed. — Cold  water  should  never  be  fed  into 
a  boiler  if  it  can  be  avoided,  but  when  necessary,  it  should 
be  caused  to  mix  with  the  heated  water  before  coding  in  con- 
tact with  any  portion  of  the  boiler. 


53 

12.  Foaming. — When  foaming  occurs  in  a  boiler,  check- 
ing the  outflow  of  the  steam  will  usually  stop  it.     If  caused 
by  dirty  water,  blowing  down  and  pumping  up  will  generally 
cure  it.     In  cases  of  violent  foaming,  check  the  draught  and 
cover  the  fires. 

13.  Air  Leaks. — Be  sure  that  all  openings  for  admission 
of  air  to  boiler  or  flue,  except  through  the  fire,  be  carefully 
stopped.     This  is  often  an  unsuspected  cause  of  serious  waste. 

14.  Blowing  Off. — If  feed-water  is  muddy  or  salt,  blow  off 
a  portion  often,  according  to    the   condition   of  the   water. 
Empty  the    boiler    every  week    or    two,  and   fill   up   fresh. 
When  surface  blow-cocks  are    used,  they   should   be    often 
opened  for  a  few  minutes  at  a  time.      Make  sure  no  water  is 
escaping  from  the  blow-off  cock  when  it  is  supposed  to  be 
closed.      Blow-off  cocks  and  check-valves  should  be  examined 
every  time  the  boiler  is  cleaned. 

15.  Leaks. — Repair  leaks  as   soon  as  possible  after  dis- 
covered. 

1 6.  Emptying  Boiler. — Never  empty  the  boiler  while  the 
brick- work  is  hot. 

17.  Rapid  Firing. — Don't  indulge  in  rapid  firing.     Steam 
should  be  raised  slowly  from  a  cold  boiler. 

18.  Standing  Unused. — If  a  boiler   is   not    required   for 
some  time,  empty  and  dry  it  thoroughly.     If  this  is  imprac- 
tical, fill  it  quite  full  of  water,  and  put   in  a  quantity  of 
common  washing  soda. 

19.  General  Cleanliness. — All  things  about  the  boiler- 
room  should  be  kept  clean  and  in  good  order.     Negligence 
tends  to  waste  and  decay. 

INJECTORS. 

In  setting  up  injectors,  be  careful  that  all  the  supply-pipes, 
steam,  water  or  delivery,  have  the  same  diameter  (internal 
diameter)  as  the  hole,  nipple,  branch,  plug,  tee,  or  reducer 
to  which  they  are  attached,  and  that  they  are  as  smooth, 
direct  and  straight  as  possible. 

Place  a  strainer  over  the  end  of  the  supply  pipe  to  keep 
out  chips,  dirt,  etc.,  but  be  careful  that  the  meshes  or  holes 
of  the  strainer  will  equal  in  area  the  area  of  the  supply-pipe. 

In  piping  for  steam  for  the  injector,  take  steam  from  the 
highest  part  of  the  boiler  so  as  to  get  dry  steam.  All  pipes 
should  be  air  and  water  tight,  otherwise  the  injector  will 
kick  back,  take  air  and  sputter.  (? 

In  case  the  water  is  not  to  be  lifted,  but  is  fed  with  a  head 


54 

from  a  tank  or  hydrant,   place   a   stop-cock  on   the   pipe  to 
keep  the  boiler  from  being  flooded. 

A  stop-valve  should  also  be  placed  in  the  steam-pi'oe,  be- 
tween the  steam-room  and  the  boiler  and  injector,  anj  a 
check-valve  between  the  \\arer-space  and  injector. 

PUMPS  FOR  SUPPLYING  BOILERS. 

N"ver  use  smaller  diameters  of  pipes  than  are  called  for  in 
tne  ta-oles  furnished  by  the  manufacturers  of  the  pump,  as  all 
makers  ot  pumi  s  kn  >w  the  capacity  and  work  to  be  done  by 
their  pumps  and  their  calculations  are  correct;  however, 
when  long  pipes  are  used  it  is  necessary  to  increase  the  diam- 
eter to  allow  for  increased  friction.  Observe  this  suggestion 
especially  in  regard  to  suction-pipes.  Use  as  few  elbows, 
T's,  and  valves  as  possible,  and  run  every  pipe  in  as  direct  a 
line  as  practicable;  use  full,  round  bends  when  convenient; 
use  Y's  instead  of  T's  when  possible.  Bends,  returns,  T's 
and  elbows  increase  friction  more  rapidly  than  length  of  pipe. 
"are  should  be  taken,  against  leaks  in  the  suction-pipe,  as 

very  small  leak  destroys  the  effectiveness  of  the  suction  of  a 
,  \mp. 

See  to  it  that  a  full  head  of  water  is  constantly  furnished 
i  » pump.  To  prevent  the  pump  from  freezing  in  cold 
M  ither,  care  should  be  taken  to  open  the  drip-plugs  and 
C(  ks  which  are  provided  for  the  purpose  of  draining  the 
p\  ip. 

vlrater  at  a  high  temperature  cannot  be  raised  any  consid- 
erable distance  by  suction.  For  pumping  very  hot  water, 
place  the  supply  high  enough  so  that  the  water  will  gravitate 
to  the  pump. 

A  large  suction-chamber  placed  on  the  suction-pipe  im- 
mediately by  the  pump  is  very  advantageous,  and  for  pumps 
running  at  high  speed  it  is  a  necessity.  Keep  the  -stuffing- 
boxes  nicely  packed.  Ordinary  speed  to  run  a  pump  is  not 
over  loo  feet  piston  travel  per  minute.  For  continuous 
boiler-feeding  service  about  half  that  speed  is  recommended. 
Take  as  good  care  of  your  pump  as  you  do  of  your  engine. 

SOME  USEFUL  INFORMATION  ABOUT  WATER. 

Doubling  the  diameter  of  a  pipe  increases  its  capacity/02^ 
times.  Friction  of  liquids  increases  as  the  square  of  velocity. 

To  find  the  pressure  in  square  inches  of  a  column  of  water. 
— Multiply  the  height  of  the  column  in  feet  by  .434,  approxi- 
mately, every  foot  elevation  is  equal  to  %  pound  pressure 
per  square  inch  ;  this  allows  for  ordinary  friction. 


55 

FRICTION   OF   WATER   IN    PIPES. 

tfr 

Friction-loss  in  Pounds  Pressure  per  square  inch,  for   each   100  feet 
of  length  in  different  size  clean  Iron   Pipes   discharging  given    quanti- 
ties of  water  per  minute. 


N 

P 

5 

10 

15 
ao 

25 
30 
35 
40 
45 
5° 
75 
xoo 

"5 

150 
175 

200 
250 
300 
350 
400 
45° 
500 
750 
1OOO 

1250 
1500 

SIZES   OF     PIPES  —  INSIDE     DIAMETER. 

K  In- 

i  In. 

xtfhi. 

*ln. 

2   In 

afcln. 

3  In. 

4  In. 

6  In. 

8    In. 

3-3 
13.0 
28.7 
50  4 
78.0 

o  84 
3  -16 
6.98 
12  3 
19.0 

o  31 
1.05 

2    38 
4.07 
6.40 

0    12 
0.47 

o-97 
1.66 
2.62 

0.12 

0.42 

48  o 

16  i 

6    ?2 

I    60 

8.15 

0.81 

4.89 

->    H? 

28.1 

9.46 

3-85 

19.66 
28  06 

II.  2 
15-2 

25.0 
30.8 

1.89 

2.66 
3-65 
4-73 
6.01 

7  43 

0.26 
o-37 
0.50 
0.65 
0.81 
0.96 

2.21 

3-88 

0.07 

0.12 

0.16 

0.20 

0.25 

0-53 
0.94 
1.46 
2.09 

The  mean  pressure  of  the  atmosphere  is  usually  estimated 
at  14.7  pounds  per  square  inch,  so  that  with  a  perfect  vacu- 
um, it  will  sustain  a  column  of  mercury  29. 9  inches,  or  a  col- 
umn of  water  33.9  feet  high. 

To  find  the  diameter  of  a  pump  cylinder  to  move  a  given 
quantity  of  water  per  minute  (100  feet  of  piston  travel  being 
the  standard  of  speed),  divide  the  number  of  gallons  by  4, 
then  extract  the  square  root,  and  the  product  will  be  the 
diameter  in  inches  of  the  pump  cylinder 

To  find  the  quantity  of  water  elevated  in  one  minute,  run- 
ning at  100  feet  of  piston  speed  per  minute,  square  the  diam- 
eter of  the  water-cylinder  in  inches  and  multiply  by  4.  Ex* 
ample:  Capacity  of  a  5 -inch  cylinder  is  desired.  The  square 
of  the  diameter  (5  inches)  is  25,  which,  multiplied  by  4, 
gives  100,  the  number  of  gallons  per  minute,  nearly. 


56 

To  find  the  horse-power  necessary  to  elevate  water  to  a 
given  height :  multiply  the  total  weight  of  the  water  in 
pounds,  by  the  height  in  feet,  and  divide  the  product  by  33,. 
ooo.  (An  allowance  of  25  per  cent,  should  be  added  for 
water  friction,  and  a  further  allowance  of  25  per  cent,  for 
loss  in  steam-cylinder. ) 

The  area  of  the  steam  piston  in  square  inches,  multiplied  by 
the  steam  pressure,  gives  the  total  amount  of  pressure  that 
can  be  exerted.  The  area  of  the  water  piston,  multiplied  by 
the  pressure  of  water  per  square  inch,  gives  the  resistance. 
A  margin  must  be  made  between  the  power  and  resistance  to 
move  the  pistons  at  the  required  speed — say  from  20  to  40  per 
cent. ,  according  to  speed  and  other  conditions. 

To  find  the  capacity  of  a  cylinder  in  gallons. — Multiplying 
the  area  in  inches  by  the  length  of  stroke  in  inches,  will  give  the 
total  number  of  cubic  inches;  divide  this  amount  by  231 
(which  is  the  cubical  contents  of  a  United  States  gallon  in 
inches),  and  the  quotient  is  the  capacity  in  gallons. 

To  find  the  quantity  of  water  that  will  be  discharged 
through  an  opening  or  pipe  in  the  sides  or  bottom  of  'a  pipe, 
tank,  barrel  or  vessel. — Multiply  the  area  of  orifice  or 
hole  in  square  inches  by  the  number  corresponding  to  height 
»f  surface  above  orifice,  as  per  table.  The  product  will  be 
the  cubic  feet  discharged  per  minute. 


Height  of 
surface  above 

Multi- 

Height    of 
surface  above 

Multi- 

Height   of 
surface  ab»ve 

Multi- 

Orifice. 

plier. 

Orifice. 

plier. 

Orifice. 

plier. 

Feet. 

Feet. 

Feet. 

I 

2-25 

18 

9-5 

40 

14.2 

Z 

I 

8 

3-2 

4-5 
5-44 
6.4 

20 

22 

9 

10. 

10.5 
n. 

"•5 

45 

g 

70 

'I'* 
1  6. 

17.4 

18.8 

10 

7-i 

28 

12. 

80 

20.  i 

12 

7-8 

30 

12.3 

90 

21.3 

14 

8.4 

32 

12.7 

100 

2*.$ 

16 

9- 

35 

13-3 

To  find  the  size  of  hole  necessary  to  discharge  a  given  quan* 
tity  of  water  under  a  given  head. — Divide  the  cubic  feet  of 
water  discharged  by  the  number  corresponding  to  height,  as 
per  table.  The  quotient  will  be  the  area  of  orifice  required 
in  square  inches. 


57 


i'a&ifsB'ig^ii^J 

Hi 

4*    tO   O    00*^   C^t-n  Ui  4^  4*.  OJ  C>  j    tO    tO    to    »H    M 

s-fft'g 

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4>  4^  ON  to  to  to  to  O  O  *^J  **>J  **-!  ^s\  4>  4^  OJ  Oj 

rr  ?r 
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ON  >^  <~r\  to   to  N<  HH 

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O*-J4^   CNO4^    O  OO  CsOJ  OJ   to  >-i    O  O   O   O 

H 

SP 

c| 

iH|i|^^p^| 

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If 

r 

% 

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^^  ^         ^^^xx 

,    w 

3    HgX 

MS  w\  M\-^X4^S^\^X                 •^\'^\^\  O^s.  O^\. 

O   OO  0s.  '--ri  Or  4^  4^  ^J  OJ    to    tO    tO    "~<    *^    "^ 

wf 

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r» 

To  find  the  height  necessary  to  discharge  a  given  quantity 
through  a  given  orifice. — Divide  the  cubic  feet  of  water  dis- 
charged by  the  area  of  orifice  in  square  inches.  The  quotient 
will  be  the  number  corresponding  to  height,  as  per  table. 

The  above  rules  represent  the  actual  quantities  that  will  be 
delivered  through  a  hole  cut  in  the  plate;  if  a  short  pipe  be 
attached  the  quantity  will  be  increased,  the  greatest  delivery 
with  a  straight  pipe  being  attained  with  a  length  equal  to  four 
times  the  diameter  of  the  hole.  If  a  taper  pipe  be  attached 
the  delivery  will  be  still  greater,  being  1*4,  times  the  delivery 
through  the  plain  orifice. 

STEAM  FOR  HEATING. 

In  estimating  for  steam-heating,  allow  one  square  foot  of 
boiler  surface  for  each  ten  square  feet  of  radiating  surface. 
Small  boilers  should  be  larger  proportionately  than  large 
boilers. 

Each  horse-power  of  boiler  will  supply  from  250  to  350  feet 
of  I  inch  pipe,  or  80  to  120  square  feet  of  radiating  surface. 

Under  ordinary  circumstances,  one  horse-power  will  heat 
about  as  follows: 

Brick  buildings  in  blocks i5>ooo  to  20,000  cubic  feet. 

Brick  stores  in  blocks 10,000  to  1 5,000     *  *       " 

Brick  dwellings,  exposed  all  sides  10,000  to  15,000     "       *{ 

Brick  mills,  shops,  etc 7,000  to  10,000     "       " 

Wooden  buildings,  exposed 7,000  to  10,000     '*       ** 

Foundries  and  wooden  shops.    ..  .6,000  to  10,000     "       " 

It  is,  of  course,  but  good  workmanship  to  make  all  the 
joints  steam  and  water  tight,  as  the  slightest  leak  in  a  steam- 
heating  system  is  apt  to  do  considerable  damage  to  furniture, 
curtains,  carpets,  etc.,  if  the  steam  is  intended  to  heat  a  dwell- 
ing. Red  or  white  lead  is  all  right  as  material  to  make  up 
joints,  but  graphite  is  much  better  (see  page  141).  For  gas- 
kets there  is  nothing  better  than  asbestos,  and  this  material 
is  now  manufactured  into  gasket  rings  cut  true  to  size,  mak- 
ing asbestos  gaskets  not  only  the  best,  but  furnished  in  a 
convenient  form  which  will  be  highly  appreciated  by  the 
steam-fitter. 

The  quality  of  rubber  sheets  sold  by  dealers  for  gaskets,  is 
sometimes  of  the  poorest  order,  and  rubber  in  any  form,  vul- 
canized or  otherwise,  is  poor  stuff  to  put  in  contact  with 
steam.  Gaskets  made  of  thin  lead  are  good,  and  first  class 
packing  can  be  made  of  candle  wicking  and  ordinary  resin 
soap,  but  asbestos  is  the  best. 


59 
THE  WESTINGHOUSE  AUTOMATIC    BRAKE. 

The  Westlhghouse  Automatic  Brake  consists  of  the  follow- 
ing essential  parts : 

I  st.  The  steam  engine  and  pump,  which  produce  the  com- 
pressed  air,  the  supply  of  steam  being  regulated  by  the  pump- 
governor. 

2d.  The  main  reservoir,  in  which  the  compressed  air  is 
stored. 

3d.  The  engineer* s  brake-valve,  which  regulates  the  flow 
of  air  from  the  main  reservoir  into  the  brake-pipe  for  releas- 
ing the  brakes,  and  from  the  brake-pipe  to  the  atmosphere  for 
applying  the  brakes. 

4th.  The  equalizing-valve ',  which  is  connected  to  a  small 
reservoir,  and  permits  the  escape  of  air  from  the  main  brake- 
pipe,  until  the  pressure  in  that  pipe  throughout  the  entire 
train  is  reduced  to  the  same  pressure  as  that  in  the  small 
reservoir,  thus  preventing  the  release  of  the  forward  brakes 
by  the  engineer  closing  the  brake-valve  too  quickly,  before 
the  pressure  in  the  rear  part  of  the  pipe  has  had  time  to  be- 
come reduced. 

5th.  The  main  brake-pipe,  which  leads  from  the  main 
reservoir  to  the  engineer's  brake-valve,  and  thence  along  the 
train,  supplying  the  apparatus  on  each  vehicle  with  air. 

6th.  The  auxiliary  reservoir,  which  takes  a  supply  of  air 
from  the  main  reservoir  through  the  brake-pipe,  and  stores  it 
for  use  on  its  own  vehicle. 

7th.  The  brake-cylinder,  .which  has  its  piston-rod  attached 
to  the  brake-levers  in  such  a  manner  that,  when  the  piston  is 
forced  out  by  air  pressure,  the  brakes  are  applied. 

8th.  The  triple  valve,  which  connects  the  brake-pipe  to 
the  auxiliary  reservoir,  and  connects  the  latter  to  the  brake- 
cylinder,  and  is  operated  by  a  sudden  variation  of  pressure  in 
the  brake-pipe  (i)  so  as  to  admit  air  from  the  auxiliary  reser- 
voir to  the  brake-cylinder,  which  applies  the  brakes,  at  the 
same  time  cutting  off  the  communication  from  the  brake-pipe 
to  the  auxiliary  reservoir,  or  (2)  to  restore  the  supply  from 
the  brake-pipe  to  the  auxiliary  reservoir,  at  the  same  time 
letting  the  air  in  the  brake-cylinder  escape,  which  releases  the 
brake. 

9th.  The  couplings,  which  are  attached  to  flexible  hose 
and  connect  the  brake-pipe  from  one  vehicle  to  another. 

The  automatic  action  of  the  brake  is  due  to  the  construc- 
tion of  the  triple  valve,  the  primary  parts  of  which  are  a 
piston  and  a  slide-valve.  A  reduction  of  pressure  in  the  brake- 
pipe  causes  the  excess  of  pressure  in  the  auxiliary  reservoir  to 


force  the  piston  of  the-  triple  valve  down,  moving  the  slide* 
valve  clown  so  as  to  allow  the  air  in  the  auxiliary  reservoir  to 
pass  directly  into  the  brake-cyl  nder  and  apply  the  brakes. 
When  the  pressure  in  the  brake-pipe  is  again  increased  above 
that  in  the  auxiliary  reservoir  the  piston  is  forced  up,  moving 
the  slide-valve  to  its  former  position,  opening  communication 
from  the  brake-pipe  to  the  auxiliary  reservoir  and  permitting 
the  air  in  the  brake-cylinder  to  escape,  thus  releasing  ihe 
brakes. 

Thus  it  will  be  seen  that  any  reduction  of  pressure  in  the 
brake-pipe  applies  the  brakes,  which  is  the  essential  feature 
of  the  automatic  brake.  If  the  engineer  wishes  to  apply 
the  brakes  he  moves  the  handle  of  the  engineer's  brake- 
valve  to  the  right,  which  first  closes  a  valve  retaining  the 
pressure  in  the  main  reservoir  and  then  permits  a  portion 
of  the  air  in  the  brake-pipe  to  escape.  To  release  the 
brakes  he  turns  the  handle  to  its  former  position,  which 
allows  the  air  in  the  main  reservoir  to  flow  into  the  brake- 
pipe,  restoring  the  pressure  and  releasing  the  brakes.  A 
valve  called  the  conductor's  valve  is  placed  in  each  car, 
with  a  cord  running  the  length  of  the  car,  and  any  of  the 
trainmen,  by  pulling  this  cord  can  open  the  valve,  which 
allows  the  air  to  escape  from  the  brake-pipe.  In  applying 
the  brake  in  this  manner  the  valve  must  be  held  open  until 
the  train  comes  to  a  stop.  Should  the  train  break  in  two 
the  air  in  the  brake-pipe  escapes  and  the  brakes  are  ap- 
plied to  both  sections  of  the  train,  and  should  a  hose  or 
pipe  burst  the  brakes  are  also  automatically  applied. 

The  gauge  shows  the  pressure  in  the  main  reservoir  and 
brake-pipe  when  they  are  connected,  and  the  pressure  in  the 
brake-pipe  alone  when  the  main  reservoir  is  shut  off  by  the 
movement  of  the  engineer's  brake-valve. 

A  stop  cock  is  placed  in  each  end  of  the  brake-pipe,  and  is 
closed  before  separating  the  couplings,  thus  preventing  an 
jpplication  of  the  brakes  when  cars  are  uncoupled. 

The  diagram  above  the  engineer's  brake-valve  shows  the 
various  positions  of  the  handle  for  applying  the  brakes  with 
any  desired  degree  of  force,  for  releasing  the  brakes,  and  the 
position  in  which  the  handle  is  to  be  kept  after  the  brakes 
have  been  released. 

Following  will  be  found  detailed  views  and  descriptions  of 
detached  portions  of  the  apparatus;  also  a  full  series  of  in- 
structions for  its  proper  use  and  maintenance.  Too  much 
importance  cannot  be  attached  to  that  portion  of  the  instruc- 
tions stating  that  engineers  should  use  care  and  moderation 


6i 

in  applying  the  brakes  for  ordina  'y  stops.  By  applying 
them  at  a  fair  distance  from  the  station,  with  moderate  force, 
the  train  is  stopped  gently  and  without  inconvenience  to  the 
passengers,  while  if  they  are  thrown  on  with  the  utmost  force 
possible,  the  train  is  jerked  in  a  manner  that  is  extremely 
disagreeable  to  the  passengers. 

AIR    PUMP- 

Referring  to  cut,  it  will  be  seen  that  the  steam  from  the 
boiler  enters  the  top  cylinder  between  two  pistons  forming 
the  main  valve.  The  upper  piston  being  of  greater  diameter 
than  the  lower,  the  tendency  of  the  pressure  is  to  raise  the 
valve,  unless  it  is  held  down  by  the  pressure  of  a  third  piston 
of  still  greater  diameter,  working  in  a  cylinder  directly  above 
the  main  valve. 

The  pressure  on  this  third  piston  is  regulated  by  the  small 
slide-valve,  working  in  the  central  chamber  on  the  top  head. 
This  valve  receives  its  motion  from  a  rod  extending  into  the 
hollow  piston  which,  as  shown  in  the  drawing,  has  a  knob  at 
its  lower  end  and  a  shoulder  just  below  the  top  head.  This 
valve  chamber  in  the  top  head,  by  a  suitable  steam-port,  is 
constantly  in  communication  with  the  steam  space  between 
the  two  pistons  of  the  main  valve.  The  steam  acting  on  the 
third  piston  and  holding  the  main  valve  down,  admits  steam 
below  the  main  piston;  as  the  main  piston  approaches  the 
upper  head,  the  reversing-valve  rod  and  its  valve  are  raised 
until  the  slide-valve  exhausts  the  steam  from  the  space  above 
the  third,  or  reversing-piston,  when  the  main  valve  is  raised 
by  the  steam  pressure  on  the  greater  area  of  its  upper  piston, 
which  movement  of  the  main  valve  admits  steam  to  the  upper 
end  of  the  main  cylinder. 

When  the  main  valve  *  .aoved  up  to  admit  steam  to  the 
upper  end  of  the  cylinder,  it  opens  an  exhaust  port  at  the 
lower  end  just  below  the  lower  steam-port,  which  latter  is 
closed  by  the  lower  piston  of  the  main  valve;  and  when  the 
main  piston  is  on  its  upward  stroke  the  upper  exhaust-port  is 
similarly  opened. 

The  air  valves  of  the  pump  are  similar  to  those  used  in  all 
pumps.  The  lift  of  a  discharge  valve  should  not  exceed  one- 
sixteenth  of  an  inch,  and  the  lift  of  receiving  valves  should 
not  exceed  one-eighth  of  an  inch.  Care  should  be  taken  to 
have  the  lift  of  the  discharge  valves  exactly  the  same,  other- 
wise the  stroke  of  the  pump  will  be  quicker  in  one  direction 
than  in  the  other. 


•must 


TRIPLE   VALVE. 

The  arrangement  of  the  auxiliary  reservoir,  cylinder  and 
triple-valve,  with  the  latter  in  section,  are  shown   in   cut 

^-gg&s..  - ..  - 


The  triple  valve  has  a  piston  5,  working  in  the  chamber  B, 
and  carrying  with  it  the  slide-valve  6.  Air  entering  from 
the  main  pipe  passes  through  the  four-way  cock  13  by  ports 
a,  r,  and  the  drain-cup  A,  and  chamber  B,  forcing  the  piston 
5  into  its  normal  position  as  shown,  thence  through  a  small 
groove  past  the  piston  into  the  valve-chamber  above,  and  into 
the  auxiliary  reservoir,  while  at  the  same  time  there  is  an  open 


64 

communication  from  the  brake-cylinder  to  the  atmosphere, 
through  the  passage  d,  e,f  ana  g.  Air  will  continue  to  flow 
into  the  auxiliary  reservoir  until  it  contains  the  same  pressure 
as  the  main  brake-pipe. 

To  apply  the  brakes  with  their  full  force,  the  pressure  in 
the  main  brake-pipe  is  allowed  to  escape,  whereupon  the 
greater  pressure  in  the  auxiliary  reservoir  forces  the  piston 
down  on  the  graduating-stem  8,  and  in  so  doing  closes  the 
feed  opening  past  the  piston.  As  the  piston  descends,  it 
moves  with  it  the  slide-valve  so  as  to  permit  the  air  to  flow 
directly  from  the  auxiliary  revcrvoir  into  the  brake-cylinder, 
which  applies  the  brakes.  The  brakes  are  released  by  re- 
admitting pressure  into  the  main  brake-pipe  from  the  main 
reservoir,  which  pressure,  being  greater  than  that  in  the 
auxiliary  reservoir,  forces  the  piston  back  to  the  position 
shown  in  the  drawing,  when  the  air  in  the  brake-cylinder 
escapes.^  To  apply  the  brakes  gently,  a  slight  reduction  is 
made  in  the  pressure  in  the  main  brake- ^pc,  which  moves 
the  piston  down  slowly  until  it  is  sroppecTi-y  ihe  graduating 
stem  8  and  spring  9,  at  this  point  the  opening  /,  in  the  slide- 
valve  is  opposite  the  port/",  and  allows  air  from  the  auxiliary 
reservoir  to  feed  through  a  hole  in  the  side  of  the  slide-valve 
and  through  the  opening  /,  into  the  brake-cylinder  ^  When 
the  pressure  in  the  auxiliary  reservoir  has  been  reduced  by 
expanding  into  the  brake-cylinder,  until  it  is  the  same  as  the 
pressure  in  the  main  brake-pipe,  the  graduating  spring  pushes 
the  piston  up  far  enough  to  close  a  small  valve  7,  which  is 
placed  in  the  feed  opening  /,  of  the  slide-valve.  This  causes 
whatever  pressure  is  in^  the  brake-cylinder  to  be  retained, 
thus  applying  the  brake  with  a  force  proportionate  to 
the  reduction  of  pressure  in  the  brake-pipe.  To  prevent 
the  application  of  the.  brakes,  from  a  slight  reduction  of 
pressure  caused  by  leakage  in  the  brake-pipe,  a  semi- 
circular groove  is  cut  in  the  body  of  the  car-cylinder,  ^  of 
an  inch  in  width,  <£,  of  an  inch  in  depth,  and  extending  so 
that  the  piston  must  travel  three  inches  before  the  groove  is 
covered  by  the  packing  leather.  A  small  quantity  of  air, 
such  as  results  from  a  leak,  passing  from  the  triple-valve  into 
the  car  cylinder,  has  the  effect  of  moving  the  piston  slightly 
forward,  but  not  sufficiently  to  close  the  groove,  which  per- 
mjts  the  air  to  flow  out  past  the  piston.  If,  however,  the 
brakes  are  applied  in  the  usual  manner,  the  piston  will  be 
moved  forward,  notwithstanding  the  slight  leak,  and  will 
cover  the  groove.  It  is  very  important  that  the  groove  shall 
be  three  inches  long,  and  shall  not  exceed  in  area  the  dimen- 
sions given  above. 


65 

When  the  handle  of  the  four- way  cock  13,  is  turned  down, 
there  is  a  direct  communication  from  the  main  brake-pipe  to 
the  brake-cylinder,  the  triple-valve  and  auxiliary  reservoir 
being  cut  out,  and  the  apparatus  can  be  worked  as  a  noa- 
automatic  brake  by  admitting  air  into  the  main  brake-pipe 
and  brake-cylinder,  to  apply  the  brakes.  When  from  any 
cause  it  is  desirable  to  have  the  brake  inoperative  on  anjr 
particular  car,  the  four-way  cock  is  turned  to  an  intermediate 
position,  which  shuts  off  the  brake-cylinder  and  reservoir, 
leaving  the  main  brake-pipe  unobstructed  to  supply  air  to 
the  remaining  vehicles. 

The  drain  cup  A  collects  any  moisture  that  may  a<?cumtt- 
late,  and  is  drained  by  unscrewing  the  bottom  nut. 

ENGINEER'S  BRAKB-VALVE. 


PLATE!  vh 


The  handle  I  of  the  engineer's  brake-valve  terminates  in  a 
screw  with  a  coarse  thread,  which  compresses  a  spring  4  upon 
the  top  valve  3;  this  top  valve  fits  into  a  slot  in  the  handle  I 


66 

and  into  a  slot  in  the  main  valve  6,  so  that  the  handle  and  the 
two  valves  must  turn  simultaneously.  In  the  position  shown 
in  the  drawing,  which  is  for  releasing  the  brakes,  the  top  valve 

3  leading  to  the  atmosphere  is  kept  closed  by  the  compression 
of  the  spring  4,  and  the  air  passes  freely  from  the  main  reser- 
voir to  the  brake-pipe  through  the  openings  of  the  main  valve 
and  the  body  of  the  brake-valve.     After  the  brakes  are  off, 
the  handle  is  moved  against  the  second  stop,  a  short  distance 
to  the  right,  which  turns  the  main  valve  so  that  the  main 
passages  to   the  break-pipe  are  closed.     Air  can,  however, 
pass  through  the  small  valve  7,  and  thence  to  the  brake-pipe 
through  a  small  opening  not  shown  in  the  drawing.     This 
small  valve  7  is  held  down  by  a  spring  whose  resistance  is 
equal  to  20  Ibs.  per  square  inch,  hence  the  pressure  in  the 
main  reservoir  will  be  20  Ibs.  greater  than  that  in  the  brake- 
pipe,  which  surplus  pressure  insures  the  certain  release  of  the 
brakes  when  desired.     To   apply   the  brakes  the  handle  is 
moved  still  further  to  the  right,  when  the  opening  from  the 
small  valve  7  is  also  closed,  cutting  off  all  communication 
from  the  main  reservoir  to  the  brake-pipe,  at  the  same  time 
the  action  of  the  screw  lifts  the  handle  and  relieves  the  spring 

4  from  pressure,  when  the  air  in  the  brake-pipe  lifts  the  valve 
3,  and  escapes,  until  an  equilibrium  is  established  between 
the  air  pressure  and  the  pressure  of  the  spring  on  the  valve  3, 
thus  reducing  the  pressure  in  the  brake-pipe  to  an  extent  cor- 
responding to  the  distance  which  this  handle  is  moved. 

To  apply  the  brakes  suddently  the  handle  is  turned  the  entire 
distance  to  the  right,  which  relieves  the  spring  ot  all  compres- 
sion, allowing  the  valve  3  to  rise,  and  all  of  the  air  in  the 
brake-pipe  to  escape. 

After  the  train  is  stopped,  the  brakes  are  released  by  turn- 
ing the  handle  to  the  position  shown  in  the  drawing. 

The  pump-governor  is  shown  in  the  cut,  the  object  of 
which  is  to  automatically  cut  off  the  supply  of  steam  to  the 
pump  when  the  air  pressure  in  the  train-pipe  exceeds  a  cer- 
tain limit,  say  70  Ibs. 

The  operation  of  this  governor  is  as  follows:  The  wheel  8 
is  screwed  down  so  as  to  permit  the  valve  10  to  be  unseated 
by  the  excess  of  pressure  on  the  upper  side  of  the  valve  per- 
mitting steam  to  pass  through  the  openings  A  and  B  to  the 
pump.  A  connection  is  made  from  the  train -pipe  to  the  up- 
per end  of  the  governor,  and  the  compressed  air  passes 
around  the  stem  14  to  the  upper  side  of  the  diaphragm  plate 
18,  which  is  held  to  its  position  by  the  spring  1 6,  which  latter 
is  of  sufficient  strength  to  resist  a  pressure  of  say,  70  lbs» 


TO  TRAM  PIPS  PUMP-GOVERNOR. 


68 

per  square  inch  on  diaphragm.  As  soon  as  the  air  pressure 
on  the  diaphragm  18  exceeds  this  amount,  it  forces  the  dia- 
phragm down,  unseating  the  valve  13,  and  allowing  the 
steam  on  the  upper  side  of  the  valve  10  to  escape  through 
the  exhaust  6,  which  causes  an  excess  of  steam  pressure  on 
the  lower  side  of  the  valve  10,  forcing  *.he  valve  against  its 
seat,  and  cutting  off  the  supply  of  steam  to  the  pump. 

When  the  pressure  in  the  train-pipe  is  diminished  by  ap- 
plying the  brakes,  the  diaphragm  is  restored  to  the  position 
shown  by  the  action  of  the  spring  16.  The  valve  13  is 
seated  by  the  spring  12,  and  the  steam  pressure  passing 
through  the  port  C,  accumulates  on  the  upper  side  of  the  valve 
jo,  forcing  it  down,  and  opening  the  passage  for  steam  to  the 
pump  until  the  air  pressure  is  again  restored  to  the  required 
limit  of  70  Ibs. 

The  use  of  the  governor  not  only  prevents  the  carrying  of 
an  excessive  air  pressure  by  the  engineers,  which  may  result 
in  the  sliding  of  the  wheels,  but  it  also  causes  the  accumulation 
of  a  surplus  of  air  pressure  in  the  main  reservoir  while  the 
brakes  are  applied,  which  insures  the  release  of  the  brakes 
without  delay.  It  also  limits  the  speed  of  the  pump  and  con- 
sequently the  wear. 

EQUALIZING  VALVE. 

The  proper  application  of  the  brakes  depends  upon  the 
amount  of  air  discharged  from  the  train  pipe,  and  the  manner 
in  which  it  is  discharged.  The  amount  of  air  to  be  dis- 
charged also  depends  upon  the  length  of  train. 

As  stated  in  the  general  description  of  the  brake  apparatus, ' 
the  brakes  are  applied  by  reducing  the  pressure  in  the  train 
pipe,  and  are  released  by  increasing  the  pressure.  On  long 
trains  engineers  have  found  it  very  difficult  to  discharge  the 
air  in  such  a  way  that  they  will  not  first  cause  a  large  reduc- 
tion in  the  front  portion  of  the  pipe,  and  then  an  increase 
tending  to  release  the  brakes  on  the  tender  and  two  or  three 
cars  next ;  the  increase  of  pressure  being  clue  to  the  expan- 
sion of  the  air  in  the  pipes  of  the  rear  portion  of  the  train. 
The  equalizing  valve  which  is  shown  in  Plate  6  (which  serves 
also  as  a  large  drain  cup),  is  a  device  which  automatically 
provides  for  the  proper  discharge  of  the  air  on  all  of  the 
vehicles,  back  of  the  tender,  the  engineer  having  to  discharge 
only  the  required  amount  from  his  brake- valve,  and  always  a 
given  amount  for  a  certain  degree  of  application,  whether  the 
train  consists  of  one  or  fifty  cars. 

In  the  position  shown,  the  air  from  the  equalizing  reservoir 
rasses  through  the  r>orts  of  the  enualizint?  valve  as  shown  by 


69 

the  arrows  and  into  the  train  pipe.  When  the  pressure  in 
the  equalizing  reservoir  is  reduced  slightly  to  apply  the 
brakes,  the  piston  15  moves  down  carrying  the  valve  II  from 
its  seat  and  permitting  the  air  in  the  train  pipe  to  escape 
through  the  ports  d,  e  and  g,  until  the  pressure  in  the  train 
pipe  equals  that  in  the  equalizing  reservoir,  when  the  piston 
and  valve  1 1  return  gradually  to  the  position  shown.  When 
it  is  desired  to  apply  the  brakes  quickly  with  full  force  a  con- 
siderable reduction  is  made  in  the  pressure  in  the  equalizing 
reservoir  and  the  piston  moves  down  its  entire  distance  car- 
rying with  it  the  slide  valve  4  and  uncovering  the  upper  port 
£•,  while  air  is  also  allowed  to  escape  through  the  port/" and 
the  lower  port  g,  thus  permitting  a  rapid  escape  of  the  press- 
ure in  the  train  pipe  until  it  equals  that  in  the  reservoir, 
when  the  valve  returns  to  the  position  shown. 

INSTRUCTIONS. 

General. — In  making  up  trains  all  couplings  must  be  united 
so  that  the  brakes  will  apply  throughout  the  entire  train. 
The  cocks  in  the  brake-pipe  must  all  be  opened  (handles  point- 
ing down),  except  that  on  the  rear  of  the  last  car,  which  must 
be  closed. 

In  detaching  engines  or  cars  the  couplings  must  invariably 
be  parted  by  hand;  the  cocks  in  the  main  brake-pipes  must 
always  be  closed  before  separating  the  couplings,  to  prevent 
application  of  the  brakes. 

If  the  brakes  are  applied  when  the  engine  is  not  attached 
to  the  train  or  car,  they  can  be  released  by  opening  the  re- 
lease cock  usually  put  in  the  end  of  the  brake-cylinder. 

The  adjustment  of  the  break-gear  should  be  such,  that 
when  the  brakes  are  full  on,  the  pistons  in  the  brake-cylinders 
will  not  have  traveled  to  exceed  eight  or  nine  inches.  This 
will  allow  for  wear  of  shoes,  stretching  of  rods,  springing  of 
brake-beams,  etc.  In  narrow  gauge  freight  apparatus  the 
adjustment  must  be  such  that  the  piston  will  not  travel  more 
than  five  or  six  inches. 

Great  care  must  be  exercised  when  taking  up  the  slack  in 
the  brake  connections  to  have  the  levers  and  pistons  pushed 
back  to  their  proper  places  and  the  slack  taken  up  by  the 
under  connection,  or  dead  levers. 

The  brake-cylinders  must  always  be  kept  clean  so  that 
they  will  readily  release  when  the  air  has  been  discharged, 
and  should  b6  oiled  once  in  three  months.  The  last  date  of 
oiling  should  be  marked  on  the  cylinder  with  chalk. 

For  the  automatic  break  the  handle  of  the  four-way  cock 
must  be  turned  horizontally.  If  turned  down  it  will  be 


70 

changed  to  the  simple  air-brake;  if  turned  midway  between 
these  two  positions,  it  will  close  communication  with  the 
brake-cylinder  and  reservoir,  and  should  be  so  turned  when 
desirable  to  have  the  brakes  out  of  use  on  any  particular  car 
on  account  of  the  breaking  of  rods,  etc.  It  is  very  important, 
in  order  to  avoid  detentions,  to  keep  the  handles  of  these 
four- way  cocks  in  their  proper  positions. 

In  cold  weather  the  triple  valve  should  be  drained  fre- 
quently, to  let  out  any  water  that  may  have  collected.  Slack 
the  bottom  nut  of  the  triple  valve  about  half  a  turn,  let  the 
water  escape  and  screw  it  up  again.  The  valve  for  the  ap- 
plication of  the  brakes  from  the  inside  of  the  car  should  be 
kept  tight,  and  must  be  examined  by  the  inspectors. 

Engineers  must  see  that  the  steam-cylinder  is  kept  well 
lubricated;  that  the  air-cylinder  is  sparingly  lubricated  with  a 
small  quantity  of  28°  gravity  West  Virginia  well  oil;  (tallow 
or  lard  oil  must  not  be  used  in  the  air-cylinder);  that  the 
pump  is  constantly  run,  but  never  faster  than  is  necessary 
to  maintain  the  required  air  pressure;  and  that  air  from  50 
to  60  pounds  pressure  for  low  speed  or  way  trains,  and  from 
70  to  80  pounds  pressure  for  express  trains  is  carried. 

For  ordinary  stops  the  brakes  should  be  applied  lightly  by 
opening  the  valve  or  cock  and  closing  it  gently  when  the 
pressure  has  been  reduced  from  4  to  8  pounds  on  the  gauge. 

The  brakes  are  fully  applied  when  the  pressure  shown  on 
the  gauge  is  reduced  20  pounds.  Any  further  reduction  is  a 
waste  of  air. 

In  releasing  the  brakes,  the  handle  of  the  brake-valve 
must  be  moved  quite  against  the  stop  and  be  kept  there  for 
about  ten  seconds,  and  then  moved  back  against  the  inter- 
mediate stop,  which  is  the  feed  position,  and  where  it  must 
remain  while  the  train  is  running. 

Engineers,  upon  finding  that  the  brakes  have  been  ap- 
plied by  the  train  men  or  automatically,  must  at  .once  aid  in 
stopping  the  train  by  turning  the  handle  of  the  brake- valve 
toward  the  right,  thus  preventing  escape  of  air  from  the  main 
reservoir. 

The  shoes  of  the  driving-wheel  brakes  should  be  so  ad- 
justed by  turning  the  screws  that  the  piston  moves  up  from 
3  to  4  inches  when  the  brakes  are  applied. 

It  is  important  to  drain  the  water  out  of  the  main  reservoir 
once  a  week,  especially  in  winter  time,  and  oftener  if  the 
pump-rod  is  not  kept  well  packed. 

If  cars  having  different  air  pressures  be  coupled  together, 
the  brakes  will  apply  themselves  on  those  which  have  the 


highest  pressure.  To  insure  the  certain  release  of  ail  the 
brakes  in  the  train,  and  also  that  trains  may  be  charged 
quickly,  the  engineer  must  carry  the  maximum  pressure  in 
the  main  reservoir  before  connecting  to  a  train,  and  then  put 
the  handle  of  his  brake-valve  in  the  release  position  until  the 
train  is  charged  with  air.  If  the  brakes  on  the  engine  and 
tender  thus  apply  themselves  by  being  coupled  to  a  train  not 
charged,  they  should  at  once  be  taken  off  by  opening  the  re- 
lease cock  from  the  brake-cylinders,  which  ought  to  be  so 
arranged  as  to  be  worked  from  the  foot-plate. 

Train- Men. — After  making  up  or  adding  to  a  train,  or 
after  a  change  of  engines,  the  rear  brakeman  shall  ascertain 
whether  the  brake  is  connected  throughout  the  train. 

When  the  hose  couplings  are  not  used  for  connecting  the 
brakes  between  two  vehicles,  they  must  be  attached  to  their 
dummy  couplings. 

When  there  is  occasion  to  apply  the  brakes  from  the  cars, 
the  valve  must  be  held  open  to  allow  the  air  to  escape  until 
the  train  is  brought  to  a  stand-still,  but  this  method  of  ap- 
plication should  only  be  used  in  cases  of  emergency. 

Train-men  must  in  all  cases  see  that  the  hand-brakes  are 
off  before  starting. 

Before  detaching  the  engine  or  any  carriages,  the  brakes 
must  be  fully  released  on  the  whole  train.  Neglecting  this 
precaution,  or  setting  the  brakes  by  opening  a  valve  or  cock 
when  the  engine  is  detached,  may  cause  serious  incon- 
venience in  switching. 

The  pipes  and  joints  must  be  kept  tight,  and  when  leaks 
are  discovered  they  should  be  corrected,  if  .serious,  before  the 
car  is  again  used. 

HOW  TO  APPLY  AND  RELEASE  THE  WESTING- 
HOUSE  AUTOMATIC  BRAKE. 

The  brakes,  as  has  been  explained,  are  applied  when  the 
pressure  in  the  brake  pipe  is  suddenly  reduced,  and  released 
when  the  pressure  is  restored.  ^ 

It  is  of  very  great  importance  that  every  engineer  should 
bear  in  mind  that  the  air  pressure  may  sometimes  reduce 
slowly,  owing  to  the  steam  pressure  getting  low,  or  from 
the  stopping  of  the  pump,  or  from  a  leakage  in  some  of  the 
pipes  when  one  or  more  cars  are  detached  for  switching  pur- 
poses, and  that  in  consequence  it  has  been  found  absolutely 
necessary  to  provide  each  cylinder  with  what  is  called  a  leak- 
age groove,  which  permits  a  slight  pressure  to  escape  with- 
out moving  the  piston,  thus  preventing  the  application  of  the 


72 

brakes  when  the  pressure  is  slowly  reduced,  as  would  result 
from  any  of  the  above  causes. 

This  provision  against  the  accidental  application  of  the 
brakes  must  be  taken  into  consideration,  or  else  it  will  some- 
times happen  that  all  of  the  brakes  will  not  be  applied  when 
such  is  the  intention,  simply  because  the  air  has  been  dis- 
charged so  slowly  from  the  Drake-pipe  that  it  only  represents 
a  considerable  leakage,  and  thus  allows  the  air  under  some 
cars  to  be  wasted. 

It  is  thus  very  essential  to  discharge  enough  air  in  the  first 
instance,  and  with  sufficient  rapidity,  to  cause  all  of  the  leak- 
age grooves  to  be  closed,  which  will  remain  closed  until  the 
brakes  have  been  released.  In  no  case  should  the  reduction 
in  the  brake-pipe  for  closing  the  leakage  grooves  be  less  than 
four  or  five  pounds,  which  will  move  all  pistons  out  so  that 
the  brake-shoes  will  be  only  slightly  bearing  against  the 
wheels.  After  this  first  reduction  the  pressure  can  be  re- 
duced to  suit  the  circumstances. 

On  a  long  train,  if  the  engineer's  brake-valve  be  opened 
suddenly,  and  then  quickly  closed,  the  pressure  in  the  brake- 
pipe,  as  indicated  by  the  gauge,  will  be  suddenly  and  consid- 
erably reduced  on  the  engine,  and  will  then  be  increased  by 
the  air  pressure  coming  from  the  rear  of  the  train  ;  hence  it 
is  important  to  always  close  the  engineer's  brake-valve  slowly, 
and  in  such  a  manner  that  the  pressure  as  indicated  by  the 
gauge  will  not  be  increased,  or  else  the  brakes  on  the  engine 
and  tender,  and  sometimes  on  the  first  one  or  two  cars  will 
come  off  when  they  should  remain  on.  It  is  likewise  very 
important,  while  the  brakes  are  on,  to  keep  the  engineer's 
brake-valve  in  such  a  position  that  the  brake-pipe  pressure 
cannot  be  increased  by  leakage  from  the  main  reservoir,  for 
any  increase  of  pressure  in  the  brake,  pipe  causes  the  brakes 
to  come  off. 

On  long  down  grades  it  is  important  to  be  able  to  control 
the  speed  of  the  train,  and  at  the  same  time  to  maintain  a  good 
working  pressure.  This  is  easily  accomplished  where  the 
pressure-retaining  valve  is  not  in  use,  by  running  the  pump 
at  a  good  speed,  so  that  the  main  reservoir  will  accumulate  a 
high  pressure  while  the  brakes  are  on.  When,  after  using 
the  brakes  some  time,  the  pressure  has  been  reduced  to  sixty 
pounds,  the  train  pipes  and  reservoirs  should  be  recharged  as 
much  as  possible  before  the  speed  has  increased  to  the  maxi- 
mum allowed.  A  greater  time  for  recharging  is  obtained  by 
considerably  reducing  the  speed  of  the  train  just  before  re- 
charging and  by  taking  advantage  of  variation  in  the  grades. 


73 

There  should  not  be  any  safety-valves  or  leaks  in  the  main 
reservoir,  otherwise  the  necessary  surplus  pressure  for 
quickly  recharging  cannot  be  obtained. 

To  release  the  brakes  with  certainty  it  is  important  to  have 
a  higher  pressure  in  the  main  reservoir  than  in  the  main 
pipe.  'If  an  engineer  feels  that  some  of  his  brakes  are  not 
off,  it  is  best  to  turn  the  handle  of  the  engineer's  brake-valve 
just  far  enough  to  shut  off  the  main  reservoir,  and  then  pump 
up  fifteen  or  twenty  pounds  extra,  which  will  insure  the  re- 
lease of  all  of  the  brakes;  all  of  which  can  be  done  while  the 
train  is  in  motion. 

For  ordinary  stops  great  economy  in  the  use  of  air  is 
effected  by,  in  the  first  instance,  letting  out  from  eight  to 
twelve  pounds  pressure,  while  the  train  is  at  speed,  taking 
care  to  begin  a  sufficient  distance  from  the  station. 

BRAKE    POWER. 

To  obtain  the  best  results,  it  is  important  to  have  the  brak- 
ing force  proportioned  to  the  weight  of  the  car,  or  more  par- 
ticularly speaking,  to  the  load  carried  by  those  wheels  upon 
which  brakes  act.  After  long  experience  it  has  been  decided 
to  recommend  such  a  proportion  of  brake  levers  that  a  press- 
ure of  fifty  pounds  per  square  inch  on  the  brake  piston  will 
bring  a  force  against  the  brake-blocks  on  each  pair  of  wheels 
equal  to  the  load  carried  by  them;  thus,  owing  to  a  great 
variation  of  cars,  it  is  impossible  to  have  uniform  brake 
levers. 

For  convenience  it  has  been  found  best  to  cut  the  brake 
connection  which  joins  the  brakes  of  both  trucks  and  to  inter- 
pose at  this  point  the  brake-cylinder,  having  with  it  two  levers 
and  a  tie-rod.  With  this  arrangement  it  is  only  necessary  to 
get  the  proper  portion  of  these  cylinder  levers. 

The  following  rules  will  enable  those  whose  duty  it  is  to 
attach  brakes  to  proportion  the  levers,  so  as  to  carry  out  the 
foregoing  recommendation. 

RULE  FOR  CALCULATING  CAR  LEVERS. 

The  air  pressure  is  rated  at  fifty  (50)  pounds  per  square 
inch  on  piston,  when  the  brakes  are  fully  applied.  (50  Ibs, 
per  square  inch  gives  about  4,000  Ibs.  for  lo-inch  cylinder, 
and  2,500  Ibs.  for  8-inch  cylinder.) 

To  find  the  leverage  required. — Divide  the  weight  of  the  car 
resting  upon  the  brake-wheels  by  the  whole  pressure  on 
piston. 

To  find  proportipn  of  brake  beam  levers. — Divide  the  whole 
length  of  lever  by  short  end. 


To  find  the  total  brake  beam  leverage. — Multiply  propor- 
tion of  lever  by  two  (2)  for  the  Hodge  system,  and  by  four  (4) 
for  the  Stevens'. 

To  find  proportion  of  cylinder  lever. — Multiply  the  whole 
length  of  lever  by  either  the  required  leverage,  or  the  total 
brake  beam  leverage,  and  divide  by  the  sum  of  both,  the  result 
will  give  the  length  of  one  end  of  the  lever. 

If  the  required  leverage  is  greater  than  the  A?fo/brake  beam 
leverage,  the  long  end  of  the  lever  must  go  next  to  the  cylin- 
der; if  less,  the  short  end  must  go  next  to  the  cylinder. 

Dead  levers  must  be  made  in  the  same  proportion  as  the 
other  truck  levers. 

Example — Hodge   System. 

Weight  of  car 36,000  Ibs. 

Total  pressure  on  lo-inch  piston 4,000  " 

Total  length  brake  beam  lever 28  inches. 

Length  of  short  end  of  brake  beam  lever     7      " 

Total  length  of  cylinder  lever 24      " 

36,000-7-4,000  =  9,  leverage  required. 

28-7-  7  =  4  X  2=  8,  total  brake  beam  leverage. 

24  X  8  =  192  -7-  (84-9)  =  11.3,  short  end  cylinder  lever. 

24  —  11.3  =  12.7,  long  end  cylinder  lever. 

Example — Stevens1  System. 
Total  length  of  cylinder  lever  36  inches. 
36,000-7-4,000=9,  leverage  required. 
28-7-7  =  4*4  —  i6»  total  brake  beam  leverage. 
36  X  9  =324 -7- (9+  16)  =  12.96,  short  end  cylinder  lever. 
36  —  12.96  =  23.04,  long  end  cylinder  lever. 

LOCOMOTIVES  IN  1832  AND  1888. 

The  Baldwin  Iron  Works,  of  Philadelphia,  in  1832  con- 
sidered it  a  great  feat  that  they  had  constructed  an  engine 
which  could  draw  thirty  tons  on  a  level,  and  the  papers  of 
the  day  contained  the  following  announcement: 

NOTICE. — The  locomotive  engine  built  by  M.  W.  Bald- 
win, of  this  city,  will  depart  daily,  when  the  weather  is  fair, 
with  a  tram  of  passenger  cars. 

tyOn  rainy  days  horses  will  be  attached. 

Now  the  same  works  are  constructing  ten-wheeled  con- 
solidated locomotives  for  the  Dom  Pedro  Railway,  in  Brazil, 
guaranteed  to  draw  3,600  tons,  with  no  reservation  as  to 
"weather." 


. 

ill 

| 

{___}     \J 
• 


75 
COLD  CHISELS. 

Figures  i  and  2  are  drawings  of  flat 
chisels.  The  difference  between  the  two  is 
that,  as  the  cutting  edge  should  be  parallel 
with  the  flats  on  the  chisel,  and  as  Fig.  I 
has  the  widest  flat,  it  is  easier  to  tell  with  it 
when  the  cutting  edge  and  the  flats  are  parallel;  therefore  the 
broad  flat  is  the  best  guide  in  holding  the  chisel  level  to  the 
surface  to  be  chipped.  Either  of  these  chisels  is  of  a  proper 
width  for  wrought  iron  or  steel,  because  chisels  used  on 
these  metals  take  all  the  power  to  drive  that  can  be  given 
with  a  hammer  of  the  usual  proportions  for  heavy  clipping, 
which  is:  Weight  of  hammer,  i#  Ibs.;  length  of  hammer- 
handle,  13  in. ;  the  handle  to  be  held  at  its  end,  and  swinging 
back  about  vertically  over  the  shoulder. 

If  so  narrow  a  chisel  be  used  on  cast  iron  or 
brass  with  full  force  hammer  blows,  it  will 
break  out  the  metal  instead  of  cutting  it,  and 
the  break  may  come  below  the  depth  wanted  to 
chip,  and  leave  ugly  cavities. 

So  for  these  metals  the  chisel  must  be  broader, 
as  in  Fig.  3,  so  that  the  force  of  the  blow  will  be  spread  over 
a  greater  length  of  chisel  edge,  and  the  edge  will  not  move 
forward  so  much  at  each  blow,  therefore  it  will  not  break  the 

metal  out. 

Another    advantage   is   that    the 
/          oroader  the  chisel  the  easier  it  is  to 
/      /  hold  its   edge  fair  with  the  work 
^XV     surface,  and  make  smooth  chipping. 
I     The  chisel-point  must  be  made  as 

L 1     thin  as  possible,  the  thickness  shown 

in  sketches    being  suitable  for  new 

chisels.  In  grinding  the  two  faces  to  form  the  chisel,  be  care- 
ful  to  avoid  grinding  them  round \  as  shown  in  a  in  the  mag- 
nified chisel  ends  in  Fig.  4;  the  proper  way  is  to  grind  them 
flat,  as  in  b  in  the  same  sketch.  Make  the  angle  or  edge  of 
these  two  faces  as  sharp  or  acute  as  you  can  because  the 
chisel  will  then  cut  easier. 

For  cutting  brass,  hold  the  chisel  about 
the  angle  shown  in  c,  Fig.  5;  for  steel, 
that  at  d  same  figure.  The  difference  is, 
that  with  hard  metal  the  more  acute 
angle  dulls  too  quickly. 

For  heavy  chipping,  the  point  may  be 
made  flat  as  in  Fig.  I.,  or  curved  as  in 


76 

Fig.  3,,  which  is  the  best,  because  the  corners  are  relieved 
from  duty,  and  are  therefore  less  liable 
to  break.  The  advantage  of  the  curve 
is  greatest  in  fine  chipping,  because,  as 
seen  in  Fig.  6,  a  liner  chip  can  be 
taken  without  cutting  with  the  corner, 
and  these  corners  are  exposed  to  the 
eye  in  keeping  the  chisel  edge  level  with 
the  work  surface. 

In  any  case  do  not  grind  the  chisel 
hollow  in  its  length,  as  in  Fig.  7,  or  as  shown 
exaggerated  in  Fig.  9,  because,  in  that  case, 
the  corners  will  dig  in  and  cause  the  chisel 
to  be  beyond  control;  besides  that,  there  will  be 
a  force,  that,  acting  on  the  wedge  principle,  will 
operate  to  spread  the  corners  and  break  them  off. 

Do  not  grind  the  faces  wider  on  one  side  than  on  the  other 
of  the  chisel,  as  in  Fig.  8,  because,  in  that  case,  the  flat  of  the 
chisel  will  form  no  guide  to  let  you  know  when  the  cutting 
edge  is  level  with  the  work  surface.  Nor  must 
you  grind  it  out  of  square  with  the  chisel  body,  as 
in  Fig.  10,  because,  in  that  case,  the  chisel  will 
be  apt  to  jump  sideways  at  each  hammer-blow. 
*««»  A  quantity  of  metal  can  be  removed  quicker  by 

using  the  cape  chisel  in  Fig.  n,  to  first  cut  out 
grooves,    spacing  these    grooves   a   little   narrower 
apart  than  the  width   of  the   flat   chisel,  and   thus 
relieving  its  corners.     The  chisel  end  must  be  shaped 
as  at  a  and  ^,  and  not  as  at  c  in  Fig. 
n,  so  as  to  be  able  to  move  it  side- 
ways, to  guide  it  in  a  straight  line, 
and  the  parallel  part  at  c  will  inter- 
fere with  this,  so  that  if  the  chisel  is 
started  a  very  little  out  of  line,  it  will  go  still 
further  out  of  line,  and   cannot   be   moved 
sideways  to  correct  the  fault. 
The   round-nosed    chisel,    Fig.    12,   must    not   be   made 
straight  on  its  convex  edge;  it  may  be  straight 
from  h  to  g  but  from  g  to  the  point,  it   must 
be  beveled,    so  that  by  altering  the  height  of 
the  chisel  head  it  is  possible  to  alter  the  depth 
of  the  cut. 

The  diamond  point  chisel  in  Fig.  14  and  15, 
must  be  shaped  to  suit  the  work,  because  if  it  is  not  to  be 
used  to  cut  out  the  corners  of  very  deep  holes,  you  can  bevel 


it  at  m,  and  these  bring  its  point  x,  central  to  the  body  of 
the  steel,  as  shown  by  the  dotted  line  q,  rendering  the 
corner  x  less  liable  to  break,  which  is  the  great  trouble  with 


this  chisel;  but  in  cutting  deep  holes  the  bevel  at  m  must 
be  omitted,  and  you  must  make  the  edge  straight,  as  at  r  in 
Fig.  15. 

The  side  chisel  obeys  the  same  rule,  so  you  may  make  it 
bevel  at  w9  as  in  Fig.  16,  for  shallow  holes,  and 
lean  it  well  over  in  using,  and  make  the  side  v  w 
straight  along  its  whole  length  for  deep  holes;  but 
in  all  chisels  for  slots  or  mortises  it  is  desirable  to 
have  if  circumstances  will  permit,  some  bevel  on  the 
side  that  meets  the  work,  so  that  the  depth  of  the 
cut  can  be  regulated  by  moving  the  chisel  head. 

In  all  these  chisels,  the  chip  on  the  work  steadies 
the  cutting  end,  and  it  is  clear,  th?t  the  nearer 
you  hold  the  chisel  at  its  head  the  steadier  yoi  can  hold  it 
and  the  less  the  liability  to  hit  your  fingers,  while  the  chipped 
surface  will  be  smoother. 

To  take  a  chip  off  wrought  iron,  if  it  is  a  heavy  chip, 
stand  well  away  from  the  vice,  as  an  old.  hand  would  do,  in- 
stead of  close  to  it;  if,  instead,  you  wish  to  take  a  light  chip, 
you  must  stand  nearer  to  the  work,  so  that  you  can  watch 
the  chisel's  action  and  keep  its  depth  of  cut  level.  In  both 
cases  you  must  push  the  chisel  forward  to  its  cut,  and  hold  it 
as  steadily  as  possible. 

It  is  a  mistake  to  move  it  at  each  blow,  as  many  do,  be- 
cause it  cannot  be  so  accurately  maintained  at  the  proper 
height.  Light  and  quick  blows  are  always  necessary  for  the 
finishing  cuts,  whatever  the  kind  of  metal  may  be. 

TURNING  OR  LATHE  TOOLS  FOR  METALS. 

Few  lathe  tools,  except  scrapers,  can  be  used  indiscrimi- 
nately for  cast  iron,  wrought  iron  or  brass;  each  metal  needs 
its  particular  set  of  tools,  differing  not  so  much  in  the  shape 
of  their  cutting  edges,  as  in  the  angles  which  they  make  with 
the  surface  of  the  work  to  be  turned.  Thus,  Figs.  17,  18, 


19  are  each  intended  to  represent  in  profile  the  ordinary 
roughing-down  tool,  but  their  angles  are  very  different,  the 
one  from  the  other.  Fig.  17  being  only  suitable  for  wrought 
iron,  Fig.  18  for  cast  iron  and  Fig.  19  for  brass.  In  all 


these,  everything  (temper  of  course  excepted)  depend  upon 
the  angle  at  which  the  tools  are  ground.  The  brass  tool  with 
the  flat  face  would  not  cut  the  iron,  but  would  simply  scratch 
it;  while  the  iron  tools  would  hitch  in  the  brass  and  tend  to 
"  chatter,"  or  "  draw-in. "  Neither  would  the  tool  ground  at 
an  acute  angle  for  wrought  iron,  cut  cast  metal,  but  would 
itself  become  broken  off  at  the  tip,  while  the  thicker  cast  iron 
tool  would  not  take  clean  shavings  offwrought  iron.  Fig.  20 
is  a  common  roughing  tool  for  cast 
iron.  The  side  view  gives  a  proper 
.angle  to  insure  a  clean  cut  without 
breaking  the  top  across  ;  in  the  di- 
rection of  the  dotted  line.  The 
angle  is  drawn  on  the  supposition 

that  the  tool  is  held  horizontally,  as  indeed  it  should  be,  but 
a  tool  that  will  not  cut  nicely  in  a  horizontal  direction  will 
often  work  by  inclining  it  at  a  slight  angle.  Neither  is  the 
angle  at  which  a  tool  should  be  ground,  in  order  to  cut  well 
horizontally,  necessarily  the  same.  It  should  be  about  65° 
with  the  verical  for  cast  iron,  but  may  vary  slightly  either 
way. 

In  fact,  not  one  workman  in  ten  could  say  what  angle  he 
grinds  his  tools  to ;  he  simply  judges  the  proper  angle  by  his 
eye.  The  angle  which  the  front  of  the  tool  makes  with  the 
work  may  vary  somewhat  more  than  the  upper  face,  depend- 
ing upon  the  diameter  of  the  work  to  be  turned,  but  should 
Dot  slope  more  than  4°  or  5°  from  the  vertical  for  cast  iron 
(Fig.  1 8).  If  it  becomes  excessive  the  tool  is  weak  and  soon 
breaks  off. 

• 

i  These  details  may  seem  trivial,  but  they  are  really  of  the 
utmost  importance.  These  sketches  are  taken  from  tools  in. 


79 

actual  use  and  doing  their  work  well.  Fig  21  shows  a  round 
nose,  Fig.  22  a  parting  tool,  Fig.  23  a  knife-tool  for  finishing 
edges  and  faces  of  flanges,  and  ends  and  sides  of  work,  either 
right  or  left-handed  (Fig.  24).  The  end  views  of  these  tools 
show  the  upper  and  clearance  angles,  which  are  about  the 
same  as  in  Fig.  1 8,  but  may  vary  somewhat  according  to  the 
work  required. 

Figs.  25  are  boring- tools  for  hollow  cylinders,  tools  capa- 


CD 


ble  of  much  modification,  their  cutting  edges  not  only  taking 
the  forms  of  all  other  tools,  but  each  form  also  being  often 
right  and  left-handed.     In  reference  to  the  more  usual  shape, 
that  of  the  round  nose  for  boring,  when  used  simply  as  a 
roughing  tool,  the  shape  b  showing  it 
in  place,  with  the  axis  of  the  cutting 
angle  in  the  direction  of  the  dotted 
line,  is  better  than  that  of  a,  because 
in  b  the  true  cutting  edge  is  carried 
**»*  forward.     Hence,  in  work-shops  the 

cutting  tools  generally  take  the  form  b,  and  the  scrapers  form^. 
Fig.  26  is  a  square  nose  for  taking  finishing  cuts,  and  Fig. 


t-, 

27  is  a  tool  for  scraping;  Fig.  28  is  a  spring  tool,  also  used 
for  finishing  a  turned  surface;  Figs.  29  and  30  are  for  finish- 
ing hollows  and  rounded  parts  of  work,  and  are  either  kept 
in  different  sweeps  or  ground  to  circles  as  wanted.  These 


Jtn, 

latter  forms  are  only  used  for  smoothing  and  polishing,  and, 
as  they  act  simply  as  scrapers,  are  flat  on  their  upper  surfaces. 

For  grinding  tools,  a  very  handy  little  grind- 
stone may  be  made  in  this  fashion  (Fig.  31).  A 
piece  of  broken  grindstone,  2  inches  thick,  is 
rudely  clipped  round  to  7  inches  in  diameter,  and 
a  yz  inch  hole  bored  through  the  center  with  a 
common  stone-bit;  two  wooden  washers,  a'9  }4 
inch  thick  by  4  inches  in  diameter,  also  have  l/2 


So 

inch  holes  bored  in  their  centers.  A  ^  inch  bolt,  b,  thrust 
through  the  whole  keeps  them  firmly  together  with  the  stone 
in  the  center. 

As  the  stone  is  intended  to  work  chucked  between  cen- 
ters, a  small  drilled  hole  is  run  both  into  the  bolt  head  and 
into  the  screwed  end,  and  a  V  shaped  slit,  c9  is  filed  in  the 
head  to  hold  the  fork. 

^  Turned  up  in  place,  it  makes  an  efficient  little  grindstone, 
in  readiness  for  use  the  moment  it  is  supped  into  the  lathe. 
A  shallow  tin  pan  slipped  between  the  stone  and  bed  will 
catch  any  mess  that  may  be  made. 

The  grindstone  or  emery  wheel  alone  is  used  to  sharpen 
roughing-down  tools;  but  those  used  for  smoothing  and  pol- 
ishing should  have  the  edge  finished  with  an  oil-stone. 

NOTES  ON  BELTING. 

Having  your  machinery,  shafting  and  pulleys  properly 
arranged,  preparatory  to  belting,  the  next  thing  to  be  deter- 
mined is  the  length  and  width  of  the  belts.  When  it  is  not 
convenient  to  measure  with  the  tape-line  the  length  required, 
the  following  rule  will  be  found  of  service: 

Add  the  diameter  of  the  two  pulleys  together;  divide  the 
result  by  2>  and  multiply  the  quotient  by  j%>  then  add  this 
product  to  twice  the  distance  between  the  centers  of  the  shafts^ 
«nd  you  have  the  length  required.  The  width  of  the  belt 
depends  on  three  conditions: — I,  The  tension  of  the  belt;  2, 
the  size  of  the  smaller  pulley  and  the  proportion  of  the  sur- 
face touched  by  the  belt;  3,  the  speed  of  the  belt. 

The  working  adhesion  of  a  belt  to  the  pulley  will  be  in 
proportion  both  to  the  number  of  square  inches  of  belt  con- 
tact with  the  surface  of  the  pulley,  and  also  to  the  arc  of  the 
circumference  of  the  pulley  touched  by  the  belt.  This  ad- 
hesion forms  the  basis  of  all  right  calculations  in  ascertaining 
the  width  of  belt  necessary  to  transmit  a  given  horse-power. 

In  locating  shafts  to  be  connected  by  belts,  care  should  be 
taken  to  secure  a  proper  distance  one  from  the  other.  This 
distance  should  be  such  as  to  allow  a  gentle  sag  to  the  belt 
when  in  motion.  A  general  rule  may  be  stated  as  thus: 
When  narrow  belts  are  to  be  run  over  small  pulleys,  15  feet 
is  a  good  average,  the  belt  showing  a  sag  of  1%  to  2  inches. 

For  larger  belts,  working  on  larger  pulleys,  a  distance  of 
20  to  25  feet  does  well,  with  a  sag  of  2%  to  4  inches. 

For  main  belts,  working  on  very  large  pulleys,  the  dis- 
tances should  be  from  25  to  30  feet,  the  belts  working  well, 
with  a  sag  of  4  to  5  inches. 


8i 

If  the  distance  be  too  great  the  weight  of  the  belt  wifl 
produce  a  very  heavy  sag,  which  is  a  decided  objection,  pro- 
ducing great  friction  on  the  bearings,  while  at  the  same  time 
the  belt  will  have  an  unsteady  flopping  motion  which  will 
destroy  both  the  belt  and  machinery.  Connected  shafts 
should  never  be  placed  one  directly  over  the  other,  as  in  that 
case  the  belt  must  be  kept  very  tight  to  do  the  work. 

It  is  best  that  the  angle  of  the  belt  with  the  floor  should 
not  exceed  45  degrees.  It  is  also  best  in  locating  the  ma- 
chinery and  shafting  so  that  the  belts  will  run  off  on  opposite 
sides,  thus  relieving  the  bearings  from  the  friction  incident  to 
having  the  tension  all  on  one  side. 

The  pulleys  should  be  of  as  large  a  diameter  as  can  be 
admitted,  provided  they  will  not  produce  a  speed  of  more 
than  3,750  feet  a  minute. 

Pulleys  should  be  a  little  wider  than  the  belts  required  for 
the  work. 

The  motion  of  driving  should  run  with,  and  not  against ^ 
the  laps  of  the  belts. 

In  using  tightening  or  guide  pulleys,  apply  them  to  the  slack 
side  of  the  belt  and  near  the  smallest  pulley.  Belts  to  run  at 
high  speed  should  be  made  as  straight  and  uniform  in  section 
and  density  as  possible;  if  practicable,  make  them  endless; 
that  is,  with  permanent  joints,  A  loose  running  belt  will  last 
and  wear  longer  than  a  tightly-drawn  belt.  Tightness  is  evi- 
dence of  overwork  and  disproportion.  Never  add  to  the  ^vork 
of  a  belt  so  much  as  to  overload  it. 

The  strongest  part  of  a  belt  leather  is  near  the  flesh  side, 
about  one-eighth  of  the  way  through  from  that  side. 

It  is  best  to  run  the  grain  (or  hair)  side  of  the  belt  next  to 
the  pulley. 

The  flesh  side  is  not  liable  to  .crack,  as  the  grain  side  will 
do  when  the  belt  is  old ;  hence,  it  is '  better  to  crimp  the 
grain  instead  of  stretch  ing  it. 

The  grain  side  next  to  the  pulley  will  give  the  belt  thirty 
per  cent,  more  power  than  if  the  flesh  side  was  on  the  pulley. 

The  belt,  as  well  as  the  pulley  adheres  best  when  smooth, 
and  the  grain  side  is  the  smoother. 

A  belt  adheres  much  better  and  is  less  liable  to  slip  when  at 
a  high  speed  than  at  a  low  speed.  Therefore  it  is  best  to  gear 
a  mill  with  small  pulleys  and  run  them  at  high  velocity,  than 
with  large  pulleys  and  to  run  them  slower.  Besides,  the  cost 
is  less,  and  appearance  much  neater. 

Keep  belts   clear   of   grease  and  accumulation  ^ 
especially  from  contact  with  lubricating  oi^ 


82 

Protect  leather  belts  from  water  and  moisture. 
Belts  should  be  kept  soft  and  pliable. 

RULES  FOR  CALCULATING  THE   HORSE-POWER.  WHICH  CAN 
BE  TRANSMITTED  BY  BELTING. 

To  find  the  horse-power  a  single  b<>lt  can  transmit  >  the  size 
of  the  pulley  and  the  width  of  the  belt  being  given. — Multiply 
the  diameter  of  the  pulley  in  inches  by  the  number  of  revolu- 
tions per  minute;  multiply  this  product  by  the  width  of  the 
belt  in  inches,  and  divide  by  2,750;  the  quotient  will  be  the 
horse-power. 

For'  a  double  belt  divide  the  last  product  by  1,925  instead 
of  2,750. 

The  horse-poiver  to  be  transmitted \  and  the  size  of  the  pulley 
being  known^to  find  the  width  of  the  belt  required. — Multiply 
the  horse-power  by  2.750  if  the  belt  is  single  (by  1,925  if  the 
belt  is  double);  also  multiply  the  diameter  of  the  pulley  in 
inches  by  the  revolutions  per  minute.  Divide  the  first  prod- 
uct by  the  last,  and  the  quotient  will  be  the  width  of  belt 
required. 

The  horse-pcnver  and  width  of  belt  being  knoivn,  to  find  the 
'diameter  of  the  pulley. — Multiply  the  horse-power  by  2,750 
for  a  single  belt  (or  1,925  if  double);  also  multiply  the  revolu- 
tions per  minute  by  the  width  in  inches;  divide  the  first  prod- 
uct by  the  last,  and  the  quotient  will  be  the  diameter  of  the 
pulley  in  Inches. 

7*he  horse -power )  diameter  of  pulley  and  width  of  belt  being 
known  j  to  find  the  number  of  revolutions  necessary. — Multiply 
the  horse-power  by  the  2,750  if  a  single  belt  (1,925  if  double); 
also  multiply  the  diameter  of  the  pulley  in  inches  by  the  width 
ei  the  belt  in  inches;  divide  the  first  product  by  the  last,  and 
the  quotient  will  be  the  number  of  revolutions  per  minute 
required. 

It  is  assumed  in  these  rules  that  the  belts  are  open,  and 
that  the  pulleys — both  driver  and  driven — are  of  same 
diameter.  If,  however,  the  pulleys  are  of  different  diameters 
the  smaller  pulley  will  have  less  surface  in  contact  with  the 
belt  than  on  the  larger  pulley.  If  this  surface — called  the 
arc  of  contact,  is  less  than  one-half  the  circumference,  the 
above  rules  must  be  modified.  In  that  case,  instead  ot  using 
the  numbers  2,750  for  single  belts,  and  1,925  for  double  belts, 
use  the  following:  When  the  arc  of  contact  of  the  smaller 
pulley  is 


I 


Single 

Belt. 

the  circumference  .....  .  .............  6,080 

...................  4,730 

..................  4,400 

................  3,850 


? 

16 

/*' 

K 


.3.220 

2,750 


Double 
Belt. 
4?25o 

3>310 
3,080 
2,700 
2,390 

2,250 

1,925 


TABLE    SHOWING    STRENGTH    OF    HELTIXG    MATERIALS. 


MATERIALS. 

Breaking 

Strain  for  i   in. 
Wide. 

Thickness. 

*K)ak-  tanned    leather 

1,250 

1-4  in. 

*t"Oak-  tanned   leather  

1,166 

1-4  in. 

•fOak-tanned   leather.  ... 

7^o 

1—4  in. 

TSucrar-tanned  leather 

721; 

1—4.  in. 

Ordinary  tanned  leather    

">So 

3—16  in. 

^3  -ply   rubber   .  .          

1,000 

7-12  in. 

TCotton-duck.      .            ... 

2OO 

"fRaw-hide  

958 

5-32  in. 

Flax  

1,489 

fTests  at  Centennial  Exposition,  1876. 

An  examination  of  this  table  will  show  that  it  will  be  safe 
to  estimate  the  breaking  strain  of  leather  and  rubber  belting 
at  4,000  pounds  to  the  square  inch  of  section,  or  1,000 
pounds  to  each  inch  of  width.  Cotton  belting  is  usually  laid 
4-ply  for  the  narrower  widths,  making,  according  to  tables,  a 
breaking  strain  of  800  pounds  to  the  inch  of  width.  This 
brings  the  three  principal  materials  very  near  together. 

It  is  usual  in  allowing  for  the  working  strength  of  belts,  to 
make  the  safe  working  strain  i  to  16  of  the  actual  breaking 
strain,  so  that  we  have  in  this  practice,  166  pounds  as  the 
working  strain  for  leather  and  rubber  to  each  one  inch  of 
width,  and  133  pounds  for  that  of  4-ply  cotton  belting. 


84 

FEED-WATER  HEATERS. 

All  water  used  in  the  generation  of  steam  for  mechanical  pur. 
Doses  is  more  or  less  heavily  impregnated  with  foreign  matter 
held  in  solution;  lime,  magnesia,  sulphur,  iron,  silica,  etc.,  or 
mud,  sand  and  vegetable  impurities  held  in  suspension. 

Where  feed-water  is  pumped  directly  into  boilers  without 
first  being  purified,  the  heat  used  for  generating  steam  sets 
free  all  impurities,  and  they  are  precipitated  upon  the  inner 
surfaces  of  the  boiler  in  the  form  of  scales  or  incrustation. 


This  scale  is  a  non-conductor  of  heat,  and  as  it  is  inter- 
posed between  the  water  and  iron  of  the  boiler,  causes  a 
7 /eat  deterioration  of  the  boiler  and  corroding  the  iron.  Be- 
sides, the  impurities  in  the  water  will  cause  priming  and  foam- 
ing, which  injures  the  engine  by  allowing  grit  to  work  into 
the  cylinder,  causing  explosions,  stoppages,  delays  and  ex- 
pensive repairs.  -> 

To  eradicate  these  evils  various  solutions  and  patented 
nostrums  are  introduced  into  the  boiler;  but  this  is  a  danger- 


ous  and  bad  practice,  as  the  majority  of  them  are  not  only 
valueless,  but  injurious.  Sal-soda,  however,  makes  a  good 
purge )  as  it  is  called,  and  may  be  used  with  good  effect  where 
the  water  causes  the  boiler  to  prime  or  foam. 

It  is  more  economical,  however,  to  purify  the  water  before 
it  is  fed  into  the  boiler,  and  to  this  end,  a  good  feed-water 
heater  and  filterer  is  necessary. 

The  subject  of  feed-water  heaters  has  not  received  much 
attention  until  within  the  last  few  years,  but  no  plant  is  now 
considered  complete  without  one.  Besides  purifying  the 
water,  the  heater  will  increase  the  temperature  of  the  water 
from  its  initial  temperature  to  200°  (in  some  heaters).  This 
it  does  by  means  of  the  exhaust  steam  from  the  engine  pass- 
ing through  it,  and  every  degree  of  temperature  raised  in  the 
feed -water,  is  so  much  clear  gain  in  economy  of  fuel,  as  the 
table  on  page  86  will  show. 

For  instance,  if  the  feed- water  enters  the  heater  at  60°  and 
is  delivered  to  the  boiler  at  1 80°,  there  is  a  saving  in  fuel  of 
10.46  per  cent.  If  the  feed-water  enters  the  heater  at  40° 
and  is  delivered  to  the  boiler  at  200°,  the  saving  in  fuel 
would  be  13.71  per  cent. 

The  cut  of  the  feed-water  heater  and  purifier  represents  a, 
standard  heater  called  the  Excelsior,  made  in  Chicago,  and 
heats  the  water  up  to  212°,  or  boiling  point. 

It  is  thus  readily  seen  that  a  saving  of  13  per  cent,  in  fuel 
by  the  use  of  a  good  feed-water  heater  is  a  matter  of  some  con* 
siderable  importance.  A  further  saving,  which  cannot  be  so 
accurately  calculated,  is  the  save  in  the  wear  and  tear  of  the 
boiler.  The  forcible  injection  of  a  stream  of  cold  water  into 
a  highly  heated  vessel  is  bound  to  make  a  sudden  variation 
in  the  degree  of  temperature,  and  any  such  variation  is  bound 
to  affect  the  boiler  to  a  greater  or  less  extent.  Where  the 
water  for  steam  purposes  is  drawn  from  the  city  pipes,  the 
consumer  is  charged  for  the  amount  of  water  he  uses,  as 
measured  by  the  water  meter.  This  expense  can  be  lowered 
fully  30  per  cent,  by  using  a  feed-water  heater,  into  which 
the  exhaust  of  the  engine  passes.  The  steam  is  condensed 
and  is  fed  back  into  the  boiler  again,  so  that  the  water,  in- 
stead of  passing  into  the  open  air  from  the  exhaust  pipe,  is 
collected  and  again  made  to  do  duty  as  steam. 
&*  The  feed-water  heater  should  be  placed  in  such  a  position 
as  to  be  easily  accessible  on  all  sides,  so  that  it  can  be  readily 
and  easily  cleansed,  and  the  sediment  removed  without  dirty- 
ing up  the  engine  or  boiler  room. 


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8? 
SETTING   SLIDE-VALVES. 

We  will  suppose  the  engine  to  be  new,  and  of  the  rocker 
type,  and  horizontal. 

First  find  in  which  direction  the  engine  is  to  run.  Set 
the  crank  on  the  forward  dead-center  by  means  of  a  square, 
or  by  a  line.  Be  sure  that  it  is  on  the  center.  Set  the  eccen- 
tric at  right  angles  to  the  crank,  high  side  turned  up.  If  the 
engine  was  to  run  the  other  way  the  eccentric  would  have  to 
be  turned  down,  or  the  engine  turned  on  the  other  center. 

To  get  the  eccentric  accurately  at  right  angles  I  us  2  the 
following  method:  I  get  a  planed  board  and  fasten  it  wher- 
ever I  can,  at  the  eccentric  side  of  the  engine,  in  such  ?  posi- 
tion that  it  will  come  under  the  eccentric  rod.  I  put  en  ths 
straps  and  rods  loosely.  I  then  hold,  or  fasten  a  pencil  to  "h 
rod,  and  have  an  assistant  turn  the  eccentric  once  arour/f, 
holding  the  pencil  so  it  will  mark  the  exact  travel  of  the  rocf 
on  the  board.  I  find  the  center  of  this  line  with  a  pair  of 
dividers  or  a  rule.  I  turn  the  eccentric  up  until  the  pencil 
comes  to  the  center  of  line.  Fasten  the  eccentric  loosely 
so  it  won't  slip.  It  is  now  at  right  angles  to  the  crank,  and 
in  the  neutral  position.  If  the  valve  had  no  lap  nor  lead  the 
eccentric  would  now  be  properly  set.  Next  I  find  the  exact 
center  of  the  valve  and  mark  it  with  a  fine  line  in  such  a 
manner  that  the  line  will  show  on  top  of  the  valve.  I  also 
find  the  center  of  all  the  parts.  I  mark  a  fine  line  running 
up  the  side  of  steam-chest  so  it  can  be  seen  above  the 
valve.  I  then  place  the  valve  over  the  parts,  and  bring 
line  on  valve  and  line  on  steam-chest,  so  they  are  together 
This  puts  the  valve  in  its  central  or  neutral  position.  I 
put  in  the  rod  and  connect  it  to  rocker-arm.  I  plumb 
the  rocker  with  a  plumb-line  and  bob  so  that  the  center  of 
eccentric  rod-pin  will  be  cut  by  the  line,  and  screw  jamb-nuts 
up  to  the  valve  with  my  fingers.  I  now  fasten  the  valve  so 
it  can't  move.  That  is,  if  I  can,  without  too  much  trouble. 
Valve,  rocker  and  eccentric  are  now  in  the  neutral  position, 
and  temporarily  fastened.  The  eccentric- rod  must  now  be 
brought  into  such  a  position  that  it  will  hook  onto  the 
rocker-arm  without  moving  it  a  hair's  breadth.  I  now  turn 
the  eccentric  the  way  the  engine  is  to  run  until  I  have  the 
proper  lead  or  opening.  If  I  have  been  accurate  in  my  work 
the  valve  is  properly  set.  To  prove  it  I  put  the  engine  on 
the  other  center,  and  if  the  lead  is  the  same  I  fasten  every- 
thing. The  valve  is  set.  The  distance  I  turned  the  eccentric 


88 

from  a  right  angle  with  the  crank  is  known  as  the  angle  of 
advance. 

POINTS  ON  BOILER'S  CIRCUMFERENCE. 
In  text-books  we  have  the  areas  and  circumferences  of 
circles,  but  if  we  don't  know  how  to  use  them,  they  are  of  no 
use  to  us.  They  are-  all  right  for  tin  or  any  thin  stuff,  but 
not  for  boiler-makers.  As  an  instance,  supposing  we  have  a 
boiler  to  make  36"  diameter.  If  we  look  at  the  table  of  cir- 
cumference we  will  find  that  it  takes  113.098" — one  hundred 
and  thirteen  inches  and  about  one-sixteenth.  This  would  not 
give  either  side  or  outside  diameter,  but  would  be  the  thick- 
ness of  iron,  less,  if  we  were  wanting  inside  measurement,  or 
more,  if  for  outside  diameter.  If  the  shell  is  of  ^"material  we 
must  add  the  %"  to  the  diameter  for  inside  diameter,  making 
it  36^".  For  this  we  will  find  that  it  takes  113.883"  or  a 
little  over  g  of  an  inch  more,  and  for  outside  diameter  we 
must  take  off  the  thickness  of  material,  making  the  diameter 
35^'  •  For  this  it  would  take  112.312",  or  about  113^5  as 
near  as  can  be  got  by  the  common  rule.  There  are  several 
ways  for  figuring  this.  My  plan  is  to  multiply  the  diameter 
by  three,  and  divide  the  same  by  seven,  and  add  the  product 
together.  But  it  must  be  understood  that  neither  this  or  the 
taking  from  tables  in  text-books  gives  laps.  In  working  this 
rule,  three  times  36^  is  108^,  and  7  into  36  will  go  5  times 
and  \  over,  but  instead  of  calling  it  \  call  it  ^,  and  we  have  it 
on  the  rule.  For  the  small  course  there  is  a  difference  of  six 
and  one-half  times  the  thickness  of  material.  This  will  hold 
good  in  all  cases,  so  that  if  we  get  one  course  out  by  figuring, 
the  other  maybe  got  by  adding  or  subtracting  this  difference. 
As  in  the  majority  of  men,  they  have  a  holy  horror  of  figures, 
especially  boiler-makers,  in  "  manufactories. "  Another  thing 
that  is  not  generally  understood  among  them  is  the  properties 
of  a  circle.  A  circular  vessel  will  contain  a  greater  quantity 
than  a  vessel  of  any  other  shape,  made  of  the  same  amount 
of  material.  That  is  to  say,  if  an  iron  plate,  six  feet  long, 
was  rolled  to  a  circle  and  a  bottom  put  in  it,  it  would  hold 
more  water  than  if  it  was  bent  square  or  any  other  shape. 
The  areas  of  circles  are  to  each  other  as  the  squares  of  their 
diameters.  Any  circle  twice  the  diameter  of  another,  is 
also  four  times  its  area  and  twice  its  circumference.  The 
diameter  of  a  circle  is  a  straight  line  drawn  through  its 
center,  touching  both  sides.  The  radius  of  a  circle  is  half  the 
diameter,  or  the  distance  fro*»  ^foe  renter  to  the  circumference. 


89 
HOW  TO  SET  A  LOCOMOTIVE   ECCENTRIC. 

I  am  familiar  with  the  rule  for  setting  a  slipped  eccentric 
by  placing  engine  on  center  and  marking  the  stem 
by  using  the  eccentric  that  is  not  slipped,  for  a  guide,  but 
what  I  want  is  a  rule  to  set  a  slipped  eccentric  without 
another  to  go  by;  suppose  I  slip  both  eccentrics  on  the  right 
side,  what  am  I  to  do,  and  why  should  I  do  it?  A. — If  both 
eccentrics  on  a  side  slip  stop  at  once,  protect  your  train,  and 
be  sure  the  eccentrics  are  slipped,  before  you  go  to  work  on 
them;  if  they  are  "off"  beyond  a  doubt,  take  off  the  chest 
cover  and  pinch  the  engine  onto  the  center  (no  matter  which 
center),  take  the  eccentric  next  the  box  first,  as  you  can  get  the 
other  out  of  the  way  to  work  at  it;  if  this  is  the  go-ahead  ec- 
centric, place  the  reverse  lever  in  forward  notch  and  turn 
the  eccentric  around  on  the  shaft  ahead  until  the  port 
opens  rV'  or  £",  the  amount  of  lead  you  want,  and  fasten  it 
there;  put  the  reverse  lever  in  the  back  notch  and  turn  the 
back-up  eccentric  back  until  the  port  is  open,  the  same  as  it 
was  with  the  go-ahead,  and  fasten  eccentric  Where  only  one 
eccentric  it  slipped,  it  is  best  to  set  it  by  marking  the  stem; 
that  plan  is  the  quickest,  as  you  do  not  have  to  take  off  the 
cover.  You  will  readily  see  that  when  one  side  is  on  the 
center,  the  engine  will  go  either  way,  as  steam  is  admitted  to 
one  side  or  the  other  of  the  piston  on  the  other  side  of  loco- 
motive, as  it  is  in  the  center  of  cylinder,  and  by  setting  the 
eccentrics  to  give  lead  on  the  center,  and  by  turning  them 
the  right  way,  you  can't  get  them  wrong.  A  good  engineer 
will  always  save  himself  all  this  trouble  and  delay  on  the  road 
by  marking  the  eccentrics  in  their  proper  position,  if  he  is 
running  a  locomotive  without  eccentric  keys. 

CHIMNEYS. 

The  following  table  shows  the  proportion  of  sizes  of  chim- 
neys to  the  horse-power  of  the  boiler  using  the  chimney. 
The  measurements  given  for  the  diameter  is  for  internal  diam- 
eter. By  referring  back  to  the  article  on  "  Steam  Boilers" 
commencing  at  page  45,  the  rules  given  for  fire  grate  surface 
can  be  utilized  in  connection  with  this  table  in  planning  for 
the  steam  power  of  a  plant.  This  table  has  been  carefully 
compiled  and  arranged,  and  the  proportions  given  may  be 
accepted  as  correct.  Too  little  attention  is  paid  to  chimneys, 
and  the  furnace  is  often  blamed  for  poor  results  when  the 
ckimney  is  the  part  in  wrong.  Proper  draught  is  all-import- 
ant, and  one  chimney  should  never  be  made  to  do  the  work 
of  two. 


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External  diameter  at  the  base  should  be  one-tenth  of  the  height,  unless  supported  by  some  other 
structure.  The"  batter"  or  taper  should  be  from  3-16  to  %  inch  to  the  foot  of  each  side. 
Thickness  of  brick  work,  one  brick  (8  or  9  inches)  for  25  feet,  from  top  downward. 
If  the  inside  diameter  exceed  5  feet,  the  top  length  should  be  i%  brick,  and  if  under  3  feet  it  may 
be  $£  brick  for  ten  feet. 

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DEFINITIONS  AND  USEFUL  NUMBERS. 

ARITHMETICAL  SIGNS    USED   IN    THIS    T.OOK. 

+    Plus,  or  more,  the  sign  of  addition,  as  2  +  2  =  4. 
—  Minus,  or  less,  the  sign  of  subtraction,  as  4  —  2  =2. 

X    signifies  multiplied  into  or  by,  as  3  X  3  —  9. 

•4-    signifies  divided  by,  as  lo  -4-  5  =  2. 

=  signifies  equality,  or  equal  to,  as  4  +  4  =  8. 
:     ::   :,  the  sign  of  proportion,  as  2  :  4  ::  3  :  6;  which  reads 

thus:  as  2  is  to  4  so  is  3  to  6. 

V  ,  the  sign  of  the  square  root,  as  A7  49  =  7 ;  that  is.  7  is 
the  square  root  of  49,  or  7  is  the  number  which,  if  multi- 
plied by  itself,  produces  49. 

72  means  the  square  of  7,  or  that  7  is  to  be  squared  or  multi- 
plied by  itself.  The  square  of  any  number  is  the  product 
of  the  number  multiplied  by  itself. 

7s  means  the  cube  of  7,  or  that  7  is  to  be  multiplied  by  7, 
and  again  by  7.  The  cube  of  any  number  is  the  product 
of  that  number  multiplied  by  itself,  and  again  by  itself. 

SQUARE   MEASURE  AND    CUBIC   MEASURE. 

144  square  inches  =  I  square  foot. 
9  square  feet      =  I  square  yard. 
1,728  cubic  inches    =  I  cubic  foot. 
27  cubic  feet         =  I  cubic  yard. 

DEFINITIONS    OF     TERMS     WHICH    ARE    EMPLOYED    IN    THE 
FOLLOWING  RULES. 

A  £ &  A  Point  has  a  position  without  mag- 

nitude, as  at  c,  Fig.  i. 

S  E F        A  Line  has  length  without  breadth, 

Figa.  1  and  2.          as  D  E,  Pig.  2. 


A   Right  Line  is  the  shortest  distance 
between  any  two  points,  P  P,  Fig.  3. 


fig  3. 


A  Superficies  has  length  and  breadth  only. 
Fig.  4. 
Fig.  4. 


92 


A  Solid  has  length,  breadth  and  thickness. 
Fig-  5- 

An  Angle  is  the  opening  of  two  lines  hav- 
ing different  directions,  and  is  either  Right, 
Acute,  or  Obtuse. 


A  Right  Angle  is  made  by  a  line  being  drawn 
perpendicular  to  another,  as  in  Fig.  6.  « 

Fig.  6* 

^S  An  Acute  Angle  is  less  than  a  Right  Angle. 

—      Fig.  7. 


An  Obtuse  Angle  is  greater  than  a  Right 
Angle.     Fig.  8. 


A  Triangle  is  a  figure  bounded   by   three   straight  lines. 
Figs.  9,  10,  ii. 

A      An  Equilateral  Triangle  is  a  Triangle  of  which  the 
three  sides  are  equal  to  each  other.     Fig.  9. 
Fig-  9- 


An  Isosceles  Triangle  has  two  of  its  sides  equal. 
Fig.  10. 


Fig.  10. 


A  Scalene  Triangle  has  all  its  sides  unequal. 
Fig.  ii. 


Fig.  11. 


93 


A  Right-angled  Triangle  has  one  Right  Angle. 
Fig.   12. 

Fig.  12- 

A  Square  is  a  4-sided  figure  having  all  its  sides 
equal,  and  all  its  angles  Right  Angles.     Fig.  13. 

p  Fig.  13. 

A  Rectangle  is  a  4-sided  figure,  having  its 
angles  Right  Angles,  and  of  which  the  length 

4  exceeds  its  breadth.     Fig.  14. 

£ig.  14. 

An  Arc  is  any  part  of  the  circum- 
ference of  a  circle,  as  A  c  B,  Fig. 


Fig.  15. 


A  Chord  is  a  right  line  joining 
the  extremities  of  an  Arc,  as  A  B, 
Fig.  15. 

A  Segment  of  a  Circle  is  any  part 
bounded  by  an  Arc  and  its  Chord, 
as  the  Segment  A  C  B,  Fig.  15. 

A  Diameter  is  a  straight  line 
passing  through  the  center  of  a 
Circle,  and  bounded  by  the  circum- 
ference at  both  ends,  asG  H,  Fig.  15. 

A  Semicircle  is  half  a  Circle,  as  G  c  II,  Fig.  15. 

The  Circumference  of  a  Circle  is  the  outside  boundary  line 
described  on  the  center  with  a  length  equal  to  the  radius. 

A  Quadrant  is  a  Quarter  Circle,  as  G  o  I,  Fig.  15. 

A  Tangent  is  a  Right  Line  that  touches  a  Circle  without 
C  cutting  it,  as  E  v,  Fig.  15. 


3  Concentric  Circles  are  Circles  hav- 
ing the  same  center,  and  the  space 
included  between  their  circumfer- 
ences is  called  a  Ring.  Fig.  16. 


Fig.  16. 


94 


USEFUL  NUMBERS  IN  CALCULATION. 


Lbs.   Pounds  x 

X 

Diameter  of  Circle  X 
Circumference  X 
Cubic  inches  X 

Cubic  feet  X 

Cylindrical  in.  X 

Cylindrical  feet  X 
Diameter  of  circle  X 
Side  of  a  square  X 


.009 

.00045  = 

3.1416  = 

.3183  = 

.003607   : 
6.232 

.002832    = 


Square  of  the    ) 
diameter         ) 
Radius  of  circle 
Cubic  inches 
Cylindrical  inches 
Cubic  ft.  of  water 
Gallons  of  water 


.88622 

1. 128 

.7854 

6.2831 


X 

•f-  277.274 
+  353-03 

X     35-9 
X     10 


Hundredweights. 

Tons. 

Circumference. 
:   Diameter. 

Gallons. 

Gallons. 

Gallons. 

Gallons. 

=  Side  of  equal  sq. 
=  Diam.  of  circle  of 
equal  area. 

=  Area  of  circle. 

=  Circumference. 

=  Gallons. 

=  Gallons. 

=  Tons. 

=  Pounds  weight. 


MENSURATION. 


To  find  the  circumference  of  a  circle  when  the  diameter  is 
given. — Multiply  the  diameter  by  3.1416;  the  product  is  the 
circumference. 

A  common  method  of  calculating  the  circumference  is  to 
multiply  the  diameter  by  3,  and  add  \  of  the  diameter  to  the 
product.  The  sum  is  the  circumference,  very  nearly.  Or, 
what  amounts  to  the  same  thing,  multiply  the  diameter  by 
22,  and  divide  the  product  by  7. 

Another  method  of  finding  the  circumference  is  to  multi- 
ply the  diameter  by  3,  and  add  -fg  inch  to  the  product  for 
every  foot-length  in  the  product.  '  The  reason  for  adding  -fy 
inch  for  each  foot  of  the  product,  is,  that  it  is  the  same  in 
effect  as  the  addition  of  }  of  the  diameter.  As  the  product 
is  equal  to  three  times  the  diameter,  the  addition  to  be  made 
per  foot  of  product  should  be  only  a  third  of  the  addition 
per  foot  of  diameter;  that  is,  instead  of  }  of  the  diameter, 
the  addition  is  ^  of  },  or  -/,-  of  the  product,  which  is  at  the 
rate  of  ^  inch  per  foot  of  the  product. 

To  find  the  diameter  of  a  circle  when  the  circumfer- 
ence is  given —  Multiply  the  length  of  the  circumference  by 
the  decimal  .3183;  the  product  is  the  diameter. 


95 

Or,  divide  the  circumference  by  3.1416;  th£  quotient 
is  the  diameter. 

Or,  multiply  the  circumference  by  7,  and  divide  the 
product  by  22;  the  quotient  is  the  diameter,  very  nearly. 

To  find  the  area  of  a  circle.  —  Square  the  diameter — that 
is  to  say,  multiply  the  diameter  by  itself,  cay,  in  inches 
— and  multiply  the  product  by  the  decimal  .7854.  The 
product  is  the  area  of  the  circle  in 
square  inches. 

To  find  the  length  of  an  arc  of  a- 
circle. — From  8  times  the  chord,  A 
D,  Fig.  17,  of  half  the  arc  A  D  E, 
subtract  the  chord  of  the  whole  arc, 
A  E,  and  divide  the  remainder  by  3. 
The  quotient  is  the  eighth  of  the 
arc,  nearly. 

Kg.  17. 

To  find  the  diameter  when  the  chord  of  an 
arc  and  the  versed  sine  are  given. — Divide 
the  square  of  half  the  chord  by  the  versed 
sine,  and  to  the  product  add  the  versed 
sine.  The  sum  \. s  the  diameter. 
Note. — The  versed  sine  is  the  height  of  the 
arc. 

fo  find  the  area  of  a  segment  of  a  ring.  x^^^X 

-  ^Multiply  half  the  sum  of  the  bounding         f  ** — *O\ 
/res  by  their  distance  apart;  the  product     *(  J*        A.  X> 
is  the  area.     Thus,  let  the  arc  A  x  D  be  90       l" T  "    J  "j 
inches  long,  and  the  arc  B  c  40  inches  long,        V  ^ — /  / 
and  the  distance  A  B  or  C  D  18  inches  long;          ^**&~S 
then  90"  +  40"  ==   130;  and  130  -r-  2  =  pjg.  ^ 

65;  and  65  X    18"  =  1 1 70  square  inches, 
the  area. 

To  find  the  area  of  a  segment  of  a  circle. — To  z/z  °f  tne 
product  of  the  chord  A  B  and  versed  ine 
n  c  D  of  the  segment,  add  the  cube  of 

the  versed  sine  divided  by  twice  the 
chord;  and  the  sum  is  the  area,  nearly. 

Thus — 

C  Given  the  chord  A  B  as  20 inches,  and 

Fig.  20.  the  versed  sine  3  inches;  required  the 

area.     20  X  3  =  60;  and  60  X  2  -f-  3 
:  40.     Then  3  inches  cubed  =3   X3  X  3  =  9  X  3  =  27; 


96 


and  27  -f-  (20  X  2)  =  .675;  and  .675  +  40  =  40.675  =  area 
nearly. 

When  the  segment  is  greater  than  a  semicircle,  find  the 
area  of  the  remaining  segment  and  deduct  it  from  the  area 
of  the  whole  circle,  the  remainder  is  the  area  of  the  seg- 
ment. 

To  find  the  area  of  a  sector  of  a  circle. — Multiply  half  the 
length  of  the  arc  by  the  radius  of  the  circle.  The  product  is 
the  area  of  the  sector.  See  Fig.  17. 

To  find  the  circumference  of  an  ellipse. — Add  the  two  dia- 
meters together;  divide  the  sum  by  2, 
and  multiply  the  quotient  by  3.1416. 
Or,  multiply  the  sum  of  the  two  dia- 

-\ HO    meters    by   1.5708.       The  product   in 

^/       either    process,    is    the  circumference, 
-5 —  nearly.     Thus — what  is  the  circumfer- 

Fi    2i.  ence  °f  an  ellipse  of  which  the  diameters 

are  10  and  14?  14  +  10  =  24;  and  24 
X  1.5708  =  37.6992;  or,  10  +  14  =  24;  and  24  -f-  2  =  12; 
and  12  X  3.1416=  37.6992  =  the  circumference  of  the 
ellipse. 

Fofind  the  area  of  an  ellipse. — Multiply  the  two  diameters 
together,  and  multiply  the  product  by  .7854.  The  final 
product  is  the  area. 

To  find  the  area  of  a  square. — Multiply  the  length  of  one 
side  by  itself,  or  square  the  side.  The  product  is  the  area. 
For  example,  a  square  has  each  side  12  inches  long;  what  is 
the  area?  12  X  12=  144  square  inches  is  the  area  of  the 
square. 

To  find  the  area  of  a  rectangle. — Multiply  the  length  by 
the  breadth;  the  product  is  the  area.  For  example,  a  rect- 
angular plate  is  24  inches  long  and  12  inches  wide;  what  is 
the  area?  24  X  12  =  288  square  inches. 

To  find  the  cubic  content  of  a  rectangular  or  cubical  body .— 
Multiply  the  length  by  the  breadth,  $ 

and  multiply  the  product  by  the  depth.         *~ 
The  last  product  is  the  cubic  content.     . 
For  example,  a  box  or  cistern  is  5  feet 
long,  2^2  feet  wide,  and  3  feet  deep; 
what  is  the  cubic  content?     5  feet  mul- 
tiplied by  2.y2  feet  makes   an   area  of  22. 
12^  square  feet;  and  \2l/2  feet   multiplied  by  three  is  equal 
to  37^  cubic  feet. 


97 


To  find  J he  cubic  content  of  a  square-ended  cylinder.— 
Find  the  area  of  one  end  by  the  rule  for  the  area  of  a  circle, 
and  multiply  the  area  by  the  length.  The  product  is  the 
cubic  content  cf  the  cylinder. 


•Fig.  23. 

Note. — The  dimensions  are  to  be  taken  all  in  inches  or  all 
in  feet.  The  square  measure  and  the  cubic  measure,  corres- 
pondingly, will  be  in  inches  or  in  feet. 

Example. — A    cylinder   is  22  inches  in  diameter  and  36 
inches  in  length,  what  is  the  cubic  content? 
22  inches.         .7854 
22  484 


44 

44 

484 


31416 
62832 
31416 


380. 1336  square  inches,  area  of  the  end. 
36 

22808016 
11404008 


13684.8096  cubic  inches,  solid  content. 

To  find  the  area  of  a  tn- 
angle. — Multiply  the  length 
of  the  base  A  B  by  the  perpen- 
dicular height  c  D,  and  divide 
the  product  by  2.  The  quo- 
tient is  the  area  of  the  tri- 
angle. 

When  the  triangle  is  equi- 
lateral, or  equal  sided,  the  area 


B 


A  D 

Fig.  24 

may  be  calculated  by  squaring  the  side,  dividing  the  square 
by  4,  and  multiplying  by  1.732. 


To  find  the  cubic  content  of  a  sphere. — Multiply  the  cube 
of  the  diameter  by  the  decimal  .5236;  the  product  is  the 
cubic  content.  For  example,  let  the  diameter  be  12  inches. 
The  cube  of  12,  or  12  X  12  X  12  =  1728,  and  1728  X  .5236 
=  904. 78  cubic  inches. 

To  find  the  content  of  a  segment  of  a  sphere. — Square  the 
radius,  or  half  diameter,  of  the  base,  and  multiply  the  square 
by  3.  To  the  product  add  the  square  of  the  height  of  the 
segment,  and  multiply  the  sum  by  the  height  and  by  the 
decimal  .5236.  The  product  is  the  content  of  the  segment. 

To  find  the  content  of  a  frustum  of  a  cone. — Square  the 
diameter  of  each  end,  and  multiply  one  diameter  by  the 
other ;  add  together  the  two  squares  and  the  product,  and 
multiply  the  sum  by  the  height  of  the  frustum  and  by 
.2618.  The  final  product  is  the  content. 

To  find  the  content  of  a  frustum  of  a  square  pyramid.— 
Add  together  the  areas  of  the  two  ends  and  the  product  of 
the  lengths  of  side  of  the  ends;  multiply  the  sum  of  the 
height,  and  divide  the  product  by  3. 

PRACTICAL  GEOMETRY  FOR  MECHANICS,   EN- 
GINEERS,   BOILER-MAKERS,   ETC. 
To  bisect  a  given  right  line. — That  is,   to  divide  it,  or 
fquare    it    across    in    two 

^ 

/ 


equal  parts.     Let  A  B,  Fig. 
25,  be  the  given  right  line. 


\ 


/AX 


Fig  26. 


\ 


HB 


Fig.  25. 


Then,  with  any  radius  greater  than  A  E— that  is  greater  than 
half  the  length  of  the  line— and  on  A  and  B,  as  centers,  de- 
scribe two  arcs  cutting  each  other  at  C  and  D;  draw  the  line 
C  E  D  through  the  intersections.  Then  c  E  D  will  be  at  right 
angles  to  A  E,  and  the  line  A  B  is  divided  into  two  equal 
parts  at  E. 


99 

To  draw  a  perpendicular  to  a  straight  line  from  one  of 
its  extremities. — Let  A  B,  Fig.  26,  be  the  given  line,  and  B  the 
extremity  from  which  the  perpendicular  is  to  be  drawn.  Take 
any  point,  c,  and  with  the  radius  c  B  describe  an  arc  of  a 
circle,  A  B  D;  draw  a  line  from  A,  through  c,  cutting  the  arc 
at  D;  then,  a  line  drawn  through  the  intersection  at  D 
from  B  will  be  perpendicular  to  A  B.  ( 

To  draw  a  perpendicular  to  a  right  line  from  a  point  with- 
out the  line;    that    is, 
0  when  the    point  is  not 

on  the  line.      Let  A  B, 
Fig.  27,   be   the   given 
line,    and   c   the  point 
through  which  the  per- 
pendicular    is     to     be 
j      drawn.     Then,  on  C  as 
~'  *  a  center,  with  any  radi- 

us greater  than  the  dis- 
tance to  the  line  A  B, 
describe  an  arc  cutting 

\,  /*  A  B  at  E  and  D;  and  on 

E  and  D  as  centers,  with 
^  yf  any  radius  greater  than 

ED,  describe  two  arcs 
cutting  each  other  at  F 

E;  a  line  drawn  through  F  and  c  will  be  perpendicular  to  A  B. 

To  draw  a  line  parallel  to 

B  if         y  a  given  straight  line. — FIR  ST, 

"  /     ..-*"*-.^      to  draw  the  parallel  at  a  giv- 

en  distance.     Let  A   B,   Fig. 

28,  be  the  given  line.     Open 

--• i  the  compasses  to  the  distance 

1>  required,   and  from  any  two 

Fig-  28.  points,  c  and  D,  describe  arcs 

E  and  F.     Draw  the  line  G  H, 
touching  the  arcs.     It  is  the  required  parallel. 

C — £. 5_B          SECOND,   to  draw  a  parallel 

/  ^v*  *    '        through  a  given  point.     Let  c, 

/  "\x  /  Fig.  29,  be  the  point.      From 

j   NX-,^  /  C  draw  any  line  C  D  to  A  B. 

^*""J =      ' J *      On  C  D,  as  centers,  describe 

Fig>  o0  arcs  D  E  and  c  F.     Cut  off  D  E 

equal  to  c  F,  and  through  the 
points  C  and  E  draw  the  parallel  G  H. 


A 


To  draw  a  rectangle  from  the  center  lines. — Draw  the  line 
A  B,  Fig.  30,  equal  to  one  of  the  center  lines,  bisect  it 

£  at  C,  draw  the  other 

•  center  line,  D  E, 
through  c,  at  right 
angles  to  A  l>;  then 
with  c  D  as  a  radius, 
and  on  B  and  A  as 

.centers,  describe 
arcs  at  H,  j,  F,  and 
G;  again  \\ith  C  A 
as  radius,  on  E  and 
D  as  centers,  de- 
scribe arcs  cutting 

.  the  arcs  at  H,  J,  F, 

:  and  G.  Join  the 
in  t  er  sect  ions  by 


D 

Fig.  30. 

straight  lines,  these  will  be  at  right  angles  and  will  form  a 
rectangle. 

To  draw  a  square  on  a  given 
line. — Let  A  B,  Pig.  31,  be  the 
given  line.  Erect  a  perpendicu- 
lar at  B,  and  on  B  as  a  center, 
with  B  A  as  a  radius,  describe  an 
arc  at  D,  and  on  D  as  a  center 
describe  another  arc  at  C.  On  A 
as  a  center,  with  the  same  radius 
describe  an  arc  cutting  the  other 
arc  at  C.  Join  the  intersections  FIR.  31. 

by  straight  lines,  and  the  square 

is  formed.  If  truly  square,  it  should  measure  the  same  length 
in  the  two  diagonal  directions;  that  is,  the  distance  A  n  should 
be  equal  to  the  distance  B  c.  A 


To  bisect  an  angle. — That  is,  to  divide 
it  in  two  equal  angles.  On  the  point  of 
the  angle,  A,  Fig.  32,  as  a  center,  with 
any  radius,  describe  an  arc  cutting  the 
sides  of  the  angle  at  D  and  E,  and  on  D  and 
E  as  centers,  describe  two  arcs  cutting  each 
other  at  F.  The  line  drawn  through  A  and 
E  will  bisect  the  angle. 


101 


Fig.  33. 


6Jto;z  a  given  right  line  to  construct 
an  equilateral  triangle. — Let  A.  B,  Fig. 
33,  be  the  given  right  line;  then  on  A 
and  B,  with  A  B  as  radius,  describe  two 
arcs  cutting  each  other  at  c,  join  A  c 
and  B  C,  and  the  triangle  ABC,  thits 
formed,  is  an  equilateral  triangle. 

In  a  given  circle  to  inscribe  a 
square. — Draw  any  two  diameters  at 
right  angles  to  each  other,  and  join 
the  extremities,  as  in  Fig.  34. 

To  inscribe  an  octagon. — First  in- 
scribe the  square,  then  bisect  the 
quarter  circles  and  join  the  extremi- 
ties. Or,  bisect  the  angle  A  o  D,  Fig. 
34,  by  the  line  o  F.  Then  D  F  is  the 
length  of  the  side  of  the  octagon. 
Fig.  34. 

To  draw  a  circle  through  thrte  given  points,  no  matter  how 
they  may  are  placed. — 
This  is  a  very  useful 
problem,  as  it  enables 
any  one  to  determine 
the  diameter  of  the  circle 
of  which  an  arc  is  a  part. 
Place  the  three  points,  f , 
I,  2, 3,  any  where.  With 
any  radius  greater  than 
half  the  distance  be- 
tween two  of  the  points, 
I  and  2,  and  on  these 
points  as  centers,  de- 
scribe two  arcs  cutting 
each  other  at  A  and  B. 
Similarly,  describe  in- 
tersecting arcs  on  the 
points  2  and  3  as  cen- 


Fig.  35. 


ters.  Draw  straight  lines  through  the  intersections  respect- 
ively, meeting  at  o.  Then  o  is  the  center  from  which  the 
arc  is  to  be  described,  with  the  radius  o  I,  which  will  pass 
through  all  the  three  points. 


To  draw  a  straight  line  equal  in  length  to  a  given  arc  of 
a  circle. — Divide  the  chord  A  B  into 
four  equal  parts;   set  off  one  of  these 
parts  from  B  to  c,  and  join  c  D.     The 
line  c  D  is  equal  to  the  length  of  half  o 

the  given  arc  nearly.  Fig.  36. 

To  describe  a  rectangle  when  the  length  of  the  diagonal 
and  that  of  one  of  the  ends  is  given. — Draw  the  diagonal 
A  B.  Bisect  it  at  the  center  o,  and  with  O  A  as  radius, 
describe  a  circle.  Set  off  the  length  of  the  end  from  A,  cut- 
ting the  circle  at  D,  and  from  B  cutting  the  circle  at  c,  and 
join  A  c,  C  B,  B  D,  and  D  A,  to  form  the  rectangle  required. 


Biff.  87.  Fig  3g. 

To  construct  a  square  whose  diagonal  only  is  given. — 
Divide  the  diagonal  into  seventeen  equal  parts.  Twelve  of 
these  parts  are  the  measure  of  the  side  of  the  square.  From 
A  take  up  twelve  parts  in  the  compasses,  and  draw  arcs  of  a 
circle  at  B  and  at  c;  and  on  D  as  a  center,  with  the  same 
radius,  draw  arcs,  cutting  those  at 
c  and  D,  and  join  the  intersec- 
tions to  form  the  square  A  B  D  c. 

Another  method. — Bisect  the 
diagonal  at  o,  by  the  perpendicular 
line  c  D;  and  on  the  center  o  and 
with  the  radius  o  B,  describe  arcs 
at  c  and  D.  Join  the  intersections 
to  form  the  square  A  C  B  D. 

To  draiu  a  square  equal  in  area 
to  a  given  circle.  — Divide  the  diame  - 
ter  A  B  into  fourteen  equal  parts: 
set  off  eleven  of  these  from  A  to  o, 


Fifr.39. 


io3 

and  from  o  draw  the  perpendicular  o  c,  cutting  the  circle  at 
c;  and  draw  A  c.  Then  A  c  is  the  side  of  a  square  of  which 
the  area  is  equal  to  that  of  the  circle.  To  complete  the  square, 

from  c  draw  a  line 
through  the  center 
of  the  circle,  cutting 
the  circumference 
at  E;  and  from  A 
draw  the  straight  line 
A  E  F,  through  the 
point  E.  This  line  is 
at  right  angles  to  A  C. 
With  the  radius  A  c, 
and  on  A  as  a  center, 
describe  an  arc  at  F ; 


Fig.  40. 


on  F,  with  the 
same  radius,  draw  an 
arc  at  G.  From  c, 
again,  draw  an  arc 
cutting  the  former  at 
G  with  the  same  ra- 
dius. Join  the  in- 
tersections, and  the 
square  is  completed. 

Or,  multiply  the  diameter  of  the  circle  by  .886226:  the 
product  is  the  side  of  a  square  of  equal  area. 

To  draw  a  square  equal  in  area  to  a  given  triangle.  — Let 
B  P  A  be  the  given  triangle.  Draw  the  perpendicular  p  c 
from  the  summit  P,  and  bisect  it.  Produce  the  side  of  the 

triangle  B  A,  and 
set  off  A  E  equal  to 
the  half  of  p  c. 
Divide  E  B  into 
two  equal  parts  at 
D;  and  on  D  as 
center,  with  D  B  as 
radius,  describe 

w  the  semicircle  E  B. 

DC  B    Draw  the  perpen- 

Fig.  41.  dicular  A  F,  cutting 

the  circle  at  F  ;  then  A  F  is  the  side  of  a  square  equal  in  area 
to  that  of  the  given  triangle. 


104 

Another  method. —  A  right-angled  triangle  being  given, 
to  construct  a  square  of  the  same  area.  Divide  the  diagonal 
into  thirty-four  equal  parts ;  set  off  ten  of  these  parts  from 

B 


Fig.  42. 

A,  and  ten  from  B,  leaving  fourteen  in  the  middle.  Draw  G  C 
and  G  E  through  the  ten  divisions,  parallel  to  F  E  and  c  F 
respectively.  The  square  c  F  E  G  has  an  area  equal  to  that 
of  the  triangle  A  B  F. 

To  produce  a  circle  equal  in  area  to  a  given  square. — 
Given  the  square   A  B  c  D;  draw  the  diagonals  and  divide 


A          ^ ^         B 

Fig.  43. 

half  a  diagonal,  o  c,  into  fifteen  equal  parts.  On  o  as 
center,  and  with  a  radius  of  twelve  of  these  parts,  describe 
a  circle.  This  circle  is  of  the  same  area  as  the  square. 

Or,  multiply  the  side  of  the  square  by  1. 12837.  The  prod- 
uct is  the  diameter  of  a  circle  equal  in  area  to  the  square  of 
which  the  side  is  given. 


IDS 


The  square  is  divided 
into  four  triangles,  each  of 
which  is  one-fourth  of  the 
square  in  area.  The  quar- 
ter circles,  whose  figures 
differ  of  course  materially 
from  those  of  the  triangles, 
have  each  the  same  area  as 
one  of  the  triangles. 

To  find  the  side  of  a 
square  which  shall  con* 
tain  the  area  of  a  given 
square  any  EVEN  number 

of  times. — Draw  the  given 
square  A  E.     The  diagonal 

F  G  is  the  side  of  a  square 


I  1          H       F 

Fig.  44. 

of  double  the  area  of  the  given  square.     Set-off  E  H,  equal  to 

the  diagonal  F  G;  then 
the  square  E  B  has  four 
times  the  area  of  the 
given  square.  C^  Set-off 
again  E  I,  equal  to  the 
diagonal  H  J  of  the 
square  EB,  and  draw  the 
square  E  C  on  that  base; 
the  square  E  c  has  twice 
the  area  of  E  B,  or  four 
times  that  of  the  square 

Fig.  45.  E  A.  Set  off  E  L  equal  to 

the  diagonal  I  K;  the  square  E  D,    erected  on  that  base,  has 

twice  the  area  of  E  C. 
And  so  on. 

To  draw  an  ellipse 
approximately,  of  a 
given  length  without 
regard  to  breadth. — 
\0  Divide  the  given 
length  into  three  equal 
parts  at  o  and  V;  and 
on  o  and  v  as  centers, 
with  A  O  as  radius, 
describe  two  circles 
cutting  each  other  at 
I  and  Kon  I  and  K  as 


io6 

with  the  diameter  of  the  circle  A  o  v  as  radius,  describe 
centers  arcs  D  E  F  G,  to  complete  the  form  of  an  ellipse. 

If  the  radius  of  the  ends  is  too  larg£  and  flat,  divide  the 
given  length  into  four  equal  parts,  Fig.  4$A,  and  describe 
three  circles  as  shown;  and  on  H  and  F  as  centers,  describe 
the  lateral  arcs  to  touch  the  first  and  third  circles,  and  so 
complete  the  figure. 

To  draw  an  ellipse  when  the  length  and  breadth  are  given 
— Draw  the  diametrical  lines  at  right  angles  to  each  other, 
intersecting  at  o.  Set  out  the  length  and  breadth  of  the 
figure  on  these  lines,  equally  from  the  center  o.  Set  off  the 
length  o  D  with  the  compasses  on  the  longer  diameter  from 
B  to  E,  and  on  o  as  a  center,  with  the  radius  o  E,  describe  the 


quadrant  E  F.  Draw  the  line  or  chord  E  F,  and  set  off  the 
half  of  it  from  E  to  G.  On  o  as  a  center,  with  o  G  as  radius, 
describe  the  circle  G  H  j  I;  then  I  and  G  are  the  centers  for 
the  segmental  arcs  at  A  and  B,  and  H  and  J  are  the  centers  for 
the  lateral  arcs  at  c  and  D. 


TABLE  OF  SQUARE  AND  CUBE  ROOTS. 


No. 

Square 
Root. 

Cube 
Root. 

No. 

Square 
Root. 

Cube 
Root. 

No. 

"""" 

Square 
Root. 

Cube 
Root. 

z 

i  . 

6 

2-449 

1.817 

6.481 

3-476 

1-16 

.031 

.020 

1-4 

2-5 

1.832 

43 

6-557 

3.503 

1-8 

.060 

.040 

1-2 

2.550 

1.866 

44 

3-16 

.089 

.059 

3-4 

2-599 

1.890 

45 

6.  708 

3-557 

.118 

.077 

7 

2.646 

1  •9I3 

46 

6.782 

3-583 

5-16 

.146 

•095 

2.602 

i  .935 

47 

6.856 

3-609 

3-8 

•  J73 

.112 

1-2 

2-739 

I-957 

48 

6.928 

3-634 

7-16 

.199 

.129 

3-4 

2.  784 

1.979 

49 

7- 

3-659 

1-2 

.225 

•145 

8 

2.828 

2. 

So 

7.071 

3.684 

Qr-l6 

.250 

1-4 

2.872 

2.021 

7.141 

3.708 

5-8 
11-16 

•275 
-299 

!i76 

.191 

1-2 

3-4 

2.915 
2.958 

2.041 
2.o6l 

52 
53 

7.211 
7.280 

r$ 

3-4 

-323 

.205 

9 

3- 

2.080 

54 

7-348 

3.780 

13-16 

.346 

.219 

3.041 

2.098 

55 

7.416 

3-803 

7-8 

•369 

•233 

1-2 

3.082 

2.II8 

56 

7-483 

3.826 

15-16 

.392 

•247 

3~4 

3.  122 

2.136 

57 

7-550 

3-849 

2 

.414 

.260 

IO 

3.162 

2.154 

58 

7.616 

3-871 

x-i6 

-436 

•  273 

II 

3-3I7 

2.224 

59 

7.681 

1-8 

.458 

.286 

12 

3-464 

2.289 

60 

7.746 

3.9*5 

3-16 

-479 

.298 

13 

3.606 

2.351 

61 

7.810 

3-937 

•5 

.310 

14 

3-742 

2.410 

62 

7.874 

3.958 

5-i6 

.521 

•322 

15 

2.466 

63 

7.937 

3-979 

3-8 

•541 

•334 

16 

4- 

2.52O 

64 

8. 

4- 

7-16 

.561 

•346 

J7 

4.123 

2-571 

65 

8.062 

4.021 

1-2 

.581 

-358 

18 

4-243 

2.621 

66 

8.124 

4.041 

9-16 

.600 

-369 

IQ 

4-359 

2.668 

67 

8.185 

4-o6z 

5-8 

.620 

.380 

2O 

4.472 

2.714 

68 

8.246 

4.082 

11-16 

-639 

•391 

21 

4-583 

2-759 

69 

8.307 

4.102 

3-4 

•658 

-402 

22 

4  -690 

2.802 

70 

8.367 

4.12* 

13-16 

-677 

•  412 

23 

4.796 

2.844 

8.426 

4.141 

7-8 

-695 

•  422 

24 

4.899 

2.885 

72 

8.485 

4.160 

15-16 

.714 

•432 

25 

5- 

2.924 

73 

8-544 

4.179 

3 

•732 

•442 

26 

5.099 

2.963 

74 

8.602 

4-108 

x-8 

.768 

.462 

27 

5-196 

3- 

75 

8.660 

4.217 

1-4 

.803 

.482 

28 

5.292 

3-037 

76 

8.718 

4-236 

3-8 

•837 

•5 

29 

5.385 

3-072 

77 

8-775 

4-254 

X-2 

.871 

.    -518 

.30 

5-477 

3-107 

78 

8.832 

4-273 

5-8 

.904 

•535 

31 

5.568 

79 

8.888 

4.291  , 

3~4 

•936 

•553 

32 

5.657 

3-175 

80 

8.944 

4-309 

7-8 

.968 

•570 

33 

5-745 

3.208 

81 

9- 

4  327 

4 

•587 

34 

5-831 

3.240 

82 

9.056 

4-345 

.061 

•619 

35 

5.916 

3.271 

83 

9.  no 

4.362 

1-2 

.121 

-651 

36 

6. 

3-302 

84 

9.165 

4-379 

3-4 

.179 

.681 

37 

6.083 

3-332 

85 

9.220 

4-397- 

5 

.236 

.710 

38 

6.164 

3-362 

86 

9.274 

4.414. 

.291 

•738 

39 

6.245 

3-391 

87 

9-327 

4-431 

1-2 

•345 

•765 

40 

6-325 

3.420 

88 

9.381 

4.448 

3-4 

.398 

.792 

6.403 

3-448 

89 

9-434 

4.465 

io8 


TABLE  OF  SQUARE  AND  CUBE  ROOTS. — Continued, 


No. 

Square 
Root. 

Cube 
Root. 

No. 

Square 
Root. 

Cube 

Root. 

No. 

Square 
Root. 

Cube 
Root. 

90 

9.487 

4.481 

138 

11.747 

5-167 

286 

13-638 

5.708 

9i 

9-539 

4.498 

J39 

11.789 

5.180 

287 

13-674 

5-7x8 

92 

9-592 

4-5I4 

140 

11.832 

5.192 

1  88 

13.712 

5.728 

93 

9.644 

4.531 

141 

11.874 

5.204 

289 

13-747 

5-738 

94 

9-695 

4-547 

142 

ir  .916 

5-217 

190 

13-784 

5.748 

95 

9-747 

4-563 

143 

11.958 

5-229 

291 

13.820 

5-758 

96 

9.798 

4-579 

144 

2. 

5-241 

292 

13-856 

5-769 

97 

9.849 

4-595 

J45 

2.041 

5-253 

193 

23.892 

5-779 

98 

9.899 

4.610 

146 

2.083 

5-265 

294 

23.928 

5.788 

99 

9-950 

4.626 

M7 

2.  124 

5-277 

195 

13.964 

5.798 

xoo 

10. 

4.641 

148 

2  .165 

5-289 

296 

24. 

5.808 

XOI 

0.049 

4-057 

149 

2.206 

5-3°i 

197 

14-035 

5-828 

202 

0.099 

4.672 

150 

2-247 

5-3I3 

198 

24.072 

5-828 

I03 

0.148 

4-687 

151 

2.288 

5-325 

200 

24.142 

5-848 

104 

0.198 

4.702 

152 

2.328 

5-335 

202 

24.212 

5.867 

105 

0.246 

4.717 

153 

12.369 

5.348 

204 

24.282 

5.886 

106 

10.295 

4-732 

154 

12.409 

5-36o 

206 

14-352 

5-905 

107 

o-344 

4-747 

155 

12.449 

5-371 

208 

24.422 

5-924 

jo8 

0.392 

4.762 

156 

12.490 

5-383 

2IO 

14.492 

5-943 

109 

0.440 

4.776 

157 

12.529 

5-394 

212 

14-560 

5.962 

no 

0.488 

4.791 

158 

12.569 

5.406 

214 

24.628 

5.981 

III 

0-535 

4-805 

159 

12.009 

5-4I7 

216 

24.696 

6. 

222 

0-583 

4.820 

160 

12.649 

5-428 

218 

24.764 

6.018 

"3 

0.630 

4.834 

161 

12.688 

5-440 

220 

24.832 

6.036 

114 

0.677 

4.848 

162 

12.727 

5-451 

222 

24.899 

6.055 

«5 

0.723 

4.862 

163 

12.767 

5.462 

224 

24.966 

6.073 

116 

0.770 

4.877 

164 

12.806 

5-473 

225 

15- 

6.082 

117 

0.816 

4.890 

165 

12.845 

5-484 

226 

15-033 

6.092 

1x8 

0.862 

4.904 

266 

12.884 

5-495 

228 

25.099 

6.209 

«9 

0.908 

4.918 

267 

22.922 

5-506 

230 

25.265 

6.226 

120 

o-954 

4.632 

268 

22.962 

5-5I7 

232 

25.232 

6.244 

221 

i. 

4.946 

269 

13- 

5-528 

234 

15.297 

6.262 

IC2 

2.045 

4-959 

270 

13-038 

5-539 

236 

15-362 

6-279 

«3 

1.090 

4-973 

272 

13-076 

5-550 

238 

15-427 

6.297 

124 

2.235 

4-986 

272 

23.214 

5-562 

240 

I5-49I 

6.224 

125 

2.280 

5- 

173 

13-152 

5-572 

242 

15-556 

6.23X 

126 

2.224 

5-oi3 

174 

23.290 

5-582 

244 

25.620 

6.248 

127 

2.269 

5.026 

175 

23.228 

5-593 

246 

25.684 

6.265 

128 

i-3i3 

5-039 

276 

23.266 

5.604 

248 

15.748 

6.282 

129 

1-357 

5-052 

277 

I3-304 

5-624 

250 

25.812 

6.299 

130 

22.402 

5.065 

278 

I3-34I 

5-625 

252 

15-874 

6.326 

131 

"•455 

5.078 

279 

'3.379 

5.635 

254 

z5-937 

6.333 

232 

22.489 

5.091 

280 

13-416 

5-646 

256 

26. 

6-349 

133 

"-532 

5.204 

282 

J3-453 

5-656 

258 

26.062 

6.366 

134 

"-575 

5.227 

282 

23.490 

5.667 

260 

26.224 

6.382 

*3S 

22.628 

5.229 

183 

13-527 

5-677 

262 

26.286 

6.398 

136 

22.662 

5.242 

284 

13-564 

5-687 

264 

26.248 

6.415 

137 

22.704 

5-155 

*85 

23.601 

5-698 

266 

26.309 

6.43* 

•5 

TABLE  OF  SQUARE  AND  CUBE  ROOTS. — Continued. 


No. 

Square 
Root. 

Cube 
Root. 

No. 

Square 
Root. 

Cube 
Root. 

No. 

Square 
Root. 

Cube 
Root. 

268 

16.370 

6.447 

360 

18.973 

7.113 

500 

22.360 

7-937 

270 

16.431 

6.463 

361 

19. 

7.  1  20 

505 

22  .  472 

7.963 

272 

16.492 

6-479 

362 

19.026 

7.  126 

22  .  583 

7.98? 

274 

16.552 

6-495 

364 

19.078 

7.140 

515 

22.693 

276 

16.613 

6.510 

366 

19.131 

7-153 

520 

22.803 

8.041 

278 

16.678 

6.  526 

368 

19.183 

7.166 

525 

22.912 

8.067 

280 

16.733 

6.542 

370 

19-235 

7-J79 

530 

23.021 

8.092 

282 

16.792 

6-557 

372 

19.287 

7.191 

535 

23.130 

8.118 

284 

16.852 

6-573 

374 

19-339 

7.204 

540 

23.237 

8.143 

286 
288 

16.911 

1  6    Q7O 

6.588 
6.603 

376 
078 

19.390 

7.217 

545 

23-345 

8.168 

8    T.Q1 

289 

iv_>.  y/>J 
17- 

6.610 

o/" 

380 

19-493 

7.241 

555 

23-558 

o.  iy.j 
8.217 

290 

17.029 

6.619 

382 

19-544 

7.225 

560 

23-664 

8.242 

292 

17.088 

6.634 

384 

19-595 

7.268 

565 

23.769 

8.267 

294 

17.146 

6.649 

386 

19.646 

7.281 

570 

23.874 

8.291 

296 

17.204 

6.664 

388 

19.697 

7-293 

575 

23.979 

8.315 

298 

17.262 

6.679 

390 

19.748 

7.306 

580 

24-083 

8-339 

300 

17.320 

6.694. 

392 

19.798 

585 

24.186 

8.363, 

302 

I7-378 

6.709 

394 

19.849 

7-331 

59° 

24.289 

8.387 

3°4 

17-435 

6.723 

396 

19.899 

7-343 

595 

24.392 

8.410 

306 

17.492 

6.738 

398 

19.949 

£-355 

600 

24.494 

8.434 

308 

17-549 

6-753 

400 

20. 

7.368 

605 

24.596 

8-457 

310 

.17.606 

6.767 

402 

20.049 

7.580 

610 

24.698 

8.480 

312 

17.663 

6.782 

404 

20.099 

7-3^- 

615 

24.799 

8.504 

17.720 

6.796 

406 

20.149 

7.404 

620 

24-899 

8-527 

316 

17.776 

6.811 

408 

20.199 

7.416 

625 

25* 

8-549 

17.832 

6.825 

410 

20.248 

7.428 

630 

25.099 

8.572 

320 

17.888 

6.839 

412 

2O.297 

7.441 

635 

25.199 

8-595 

322 

17.944 

6.854 

414 

20.346 

7-453 

640 

25.298 

8.617 

324 

18. 

6.868 

416 

20.396 

7-465 

645 

8.640 

326 

18.055 

6.882 

418 

20.445 

7-476 

650 

25.495 

8.6*2 

328 

18.110 

6.896 

420 

20.493 

7-488 

655 

25-592 

8.68st 

33° 

18.165 

6.910 

422 

20.542 

7-5 

660 

25.690 

8.706 

332 

18.220 

6.924 

425 

20.615 

665 

25.787 

8.728 

334 

18.275 

6.938 

430 

20.736 

7-547 

670 

25.884 

8.750 

336 

18.330 

6.952 

435 

20.857 

7-576 

675 

25.980 

8.772 

338 

18.384 

6.965 

440 

20.976 

7.605 

680 

26.076 

8.793 

340 

18.439 

6-979 

445 

21.095 

685 

26.  172 

8.815 

342 

18.493 

6-993 

450 

21.213 

7-663 

690 

26.267 

8.836 

343 

18.520 

7- 

455 

21.330 

7.691 

695 

26.362 

8  857 

344 

18.547 

7.006 

460 

21-447 

7.719 

700 

26.457 

8.879 

346 

18.601 

7.020 

465 

21.563 

7-747 

7°5 

26.551 

8.900 

348 

18.654 

7-033 

470 

21  .679 

7-774 

710 

26.645 

8.921 

350 

18.708 

7.047 

475 

21.794 

7.802 

1  7*5 

26.739 

8.942 

352 

18.761 

7.060 

480 

21.908 

7.829 

720 

26.832 

8.96a 

354 

18.8x4 

7.074 

485 

22.022 

7-856 

i  725 

26.925 

8.983 

356 

18.867 

7.087 

490 

22.13£ 

7.883 

730 

27.018 

9.^04 

358 

18.920 

7,100 

I  495 

22.248 

7  Qi° 

1  735 

27  no 

9.024 

tf\ 

TABLE  OF  SQUARE  AND  CUBE  ROOTS. — Contimu 


No. 

Square 
Root. 

Cube 
Root. 

No. 

Square 
Root. 

Cube 
Root. 

No. 

Square 
Root. 

Cube 
Root. 

740 

27.202 

9-°45 

820 

28.635 

9-359 

900 

30. 

9.654 

745 
75<> 

27-294  . 
27.386  < 

9.065 
9.085 

825 
830 

28.722 
28.809 

9.378 
9-397 

905 
910 

30.083 

30.166 

9-67* 
9.690 

755 

27.477 

9.105 

83S 

28.896 

9.416 

915 

30-248 

9.708 

760 

27-568 

9.125 

840 

28.982 

9-435 

920 

30-33I 

9.725 

765 

27.658 

9-M5 

845 

29.068 

9-454 

925 

30-413 

9-743 

770 

27.748 

9.165 

850 

29-154 

9.472 

93° 

30.496 

9.761 

775 
780 

27-838 
27.928 

9.185 
9.205 

855 
860 

29.240 

29-325 

9.491 
9-509 

940 
950 

30.659 
30.822 

9-796 
9-830 

785 

28.017 

9.224 

865 

29-410 

9.528 

960 

30.983 

9.864 

79° 

28  .  106 

9  244 

870 

29-495 

9.546 

970 

31  •  *44 

9.898 

795 

28.195 

9.263 

875 

29.580 

9.564 

980 

3I-3°4 

9.932 

800 

28.284 

9.283 

880 

29.664 

9.582 

990 

31.464 

9-966 

805 

28.372 

9.302 

885 

29.748 

9.600 

IOOO 

31.623 

10. 

810 

28.460 

9.321 

890 

29.832 

9.619 

I  TOO 

33-J66 

10.323 

«i5 

28.548 

9-340 

895 

29.916 

9.636 

I2OO 

34-64I 

10.627 

HOW  TO  GEAR  A  LATHE  FOR  SCREW 
CUTTING. 

There  is  a  long  screw  upon  every  screw-cutting  lathe, 
called  the  lead-screw.  This  lead-screw  feeds  the  carriage  of 
the  lathe  while  cutting  screws,  and  has  a  gear  wheel  placed 
upon  its  end  which  takes  motion  from  another  gear  wheel 
attached  on  the  end  of  the  spindle.  Each  of  these  gear 
wheels  contain  a  different  number  of  teeth,  so  that  different 
threads  may  be  cut.  All  threads  are  cut  a  certain  number 
to  the  inch,  from  one  to  fifty  or  more.  In  order  to  gear  your 
lathe  properly  to  cut  a  certain  number  of  threads  to  the 
inch,  you  will  first  multiply  the  number  of  threads  to  the 
inch  you  wish  to  cut  by  4,  or  any  other  small  number,  and 
this  will  give  you  the  proper  gear  to  put  on  the  lead-screw. 
Now.  with  the  same  number,  4,  multiply  the  number  of 
threads  to  the  inch  in  the  lead-screw,  and  this  will  give  you 
the  proper  gear  to  put  on  the  spindle. 

Example.— You  wish  to  cut  a  screw  with  ten  threads  to  the 
inch.  Multiply  10  by  4  and  it  will  give  you  40;  put  this  gear 
on  the  lead-screw.  The  lead-screw  on  your  lathe  has  7 
threads  to  the  inch:  multiply  7  by  4,  and  you  will  have  28. 
Put  this  gear  on  your  spindle,  and  your  lathe  is  geared  to 
cut  10  threads  to  the  inch 


Ill 

The  rule  above  is  for  those  lathes  which  have  not  a  stud 
grooved  into  the  spindle.  As  this  stud  runs  with  but  half 
the  speed  of  the  spindle,  you  must  change  the  rule  somewhat. 

First,  multiply  the  number  of  threads  to  the  inch  you  wish 
to  cut,  by  4  (or  some  other  small  number),  and  this  will  give 
you  the  proper  gear  to  put  on  your  lead-screw.  Next  multi- 
ply the  number  of  threads  to  the  inch  on  your  lead-screw  by 
the  same  number,  and  multiply  this  product  by  <?,  and  this 
will  give  you  the  proper  gear  to  go  on  your  stud. 

Example. — Using  same  numbers — 10  times  4  is  40.  Put  this 
gear  on  your  lead-screw;  7  times  4  is  28,  and  2  times  28  is  56$ 
put  this  gear  on  your  stud,  and  your  lathe  is  grooved  to  cut 
lo  threads  to  the  inch. 


THE    THEORY     OK    THE     STEAM    ENGINE. 

For  many  year-;  engineers  cared  nothing  about  the 
theory  of  the  steam  ea^ine.  They  went  on  improving 
and  developing  it  without  any  assistance  from  men  of  pure 
science.  Indeed  it  may  he  said  with  truth  that  the  greatest 
improvement  ever  effected,  the  introduction  of  the  com- 
pound engine,  was  made  in  spite  of  the  physicist,  who  always 
asserted  that  nothing  in  the  way  of  economy  of  fuel  was  to 
be  gained  by  having  two  cylinders  instead  of  one.  In  like 
manner,  the  mathematical  theorist  was  content  to  make  cer- 
tain thermo-dynamic  assumptions,  and,  reasoning  from  them, 
to  construct  a  theory  of  the  steam  engine,  without  troubling 
his  head  to  consider  whether  his  theory  was  or  was  not  con- 
sistent with  practice.  Within  the  last  few  years,  however, 
the  theorist  and  the  engineer  have  come  a  good  deal  into 
contact,  and  the  former  begins  at  last  to  see  that  the  theory 
of  the  steam  engine  is  laid  down  by  Rankine,  Clausius,  and 
other  writers,  must  be  deeply  modified,  if  not  entirely  re- 
written, before  it  can  be  made  to  apply  in  practice  We 
have  recently  shown  what  M.  Hirn,  who  combines  in  himself 
practical  and  theoretical  knowledge  in  an  unusual  degree, 
has  had  to  say  concerning  the  received  theory  of  the  steam 
engine,  and  its  utter  inutility  for  practical  purposes  ;  and 
papers  recently  read  before  the  Institutions  of  Mechanical 
and  Civil  Engineers,  and  the  discussions  which  followed 
them,  have  done  something  to  convince  mathematicians  that 
they  have  a  good  deal  to  learn  yet  about  the  laws  which 
determine  the  efficiency  of  a  steam  engine.  It  has  always 
been  the  custom  to  class  the  steam  engine  with  other  heat 
engines.  It  is  now  known  that  nothing  can  be  more  errone- 
ous. The  steam  engine  is  a  heat  engine  sni  generis,  and  to 
confound  it  with  a  hot-air  engine,  or  any  motor  working 
with  a  non-condensible  fluid,  is  a  grave  mistake.  It  is  not 
too  much  to  say  that  many  engineers  now  understand  the 
mathematical  theory  of  the  steam  engine  better  than  do 
men  making  thermo-dynamics  a  special  study.  But  there 
remains  a  large  number  of  engineers  who  do  not  as  yet  quite 
see  their  way  out  of  certain  things  which  puzzle  them,  or 
which  they  fail  to  understand.  There  are,  indeed,  phe- 
nomena attending  the  use  of  steam  which  are  not  yet  quite 
comprehended  by  any  one,  and  we  may  be  excused  if  we  say 
something  about  one  or  two  points  which  require  elucidation. 
^One  of  these  is  the  mode  of  operation  of  the^' Steam 
jacket.  It  is  a  very  crude  statement  that  it  does  good  be- 
cause it  keeps  the  cylinder  hot.  It  might  keep  the  cylinder 


hot,  and  yet  be  a  source  of  loss  rather  than  gain  ;  and,  a^  a 
matter  of  fact,  it  is  doubtful  now  if  the  application  of  steam 
jackets  to  all  the  cylinders  of  a  compound  engine  is  advisa- 
ble. It  is  well  known,  too,  that  circumstances  may  arise, 
under  which  the  jacket  is  powerless  for  good.  Thus,  for 
example,  the  late  Mr.  Alfred  Barrett,  when  manager  of  the 
Reading  Iron  Works,  carried  out  a  very  interesting  series  of 
experiments  with  a  horizontal  engine,  in  order  to  test  the 
value  of  the  jacket.  This  engine  had  a  single  cylinder  fitted 
with  a  very  thin  wrought -iron  liner,  between  which  and  the 
cylinder  was  a  jacket  space.  The  jacket  was  very  carefully 
drained,  and  could  be  used  either  with  steam  or  air  in  it. 
Experiments  were  made  on  the  brake  with  and  without 
steam  in  the  jacket.  The  result  was  a  practically  infinitesi- 
mal gain  by  using  steam  in  the  jacket.  In  one  word,  the 
loss  by  condensation  was  transferred  from  the  cylinder  to 
the  jacket.  On  the  other  hand,  it  is  well  known  that  single 
cylinder  condensing  engines  must  be  steam  jacketed  if  they 
are  to  be  fairly  economical.  Circumstances  alter  cases,  and 
the  circumstances  which  attend  the  use  of  the  jackets  a.:-- 
more  complex  than  appears  at  first  sight. 

In  considering  the  nature  of  the  work  to  be  done,  we 
must  repeat  a  fundamental  truth  which  we  have  been  the  first 
to  enunciate.  A  steam  engine  can  discharge  no  water  from 
it  which  it  did  not  receive  as  water,  save  the  small  quantity 
which  results  from  loss  by  external  radiation  and  conduction 
from  the  cylinder,  and  from  the  performance  of  work.  At 
first  sight,  the  proposition  looks  as  though  it  were  untrue. 
Its  accuracy  will,  however,  become  clear  when  it  is  carefully 
considered.  After  the  engine  has  been  fully  warmed  up,  the 
cycle  of  events  is  this:  Steam  is'admitted  to  the  cylir.der  from 
the  boiler.  A  portion  of  this  is  condensed.  It  parts  with 
its  heat  to  the  metal  with  which  it  is  in  contact.  The  piston 
makes  its  stroke,  and  the  pressure  falls.  The  water  mixed 
with  the  steam  is  then  too  hot  for  the  pressure.  It  boils  and 
produces  steam,  raising  the  toe  of  the  diagram  in  a  way  well 
understood  and  needing  no  explanation  here.  During  the 
return  stroke  the  pressure  falls  to  its  lowest  point,  and  the 
water,  being  again  too  hot  for  the  pressure,  boils,  and  is  con- 
verted into  steam,  which  escapes  to  the  atmosphere  or  con- 
denser without  doing  work,  and  is  wasteA  The  metal  of  the 
cylinder,  etc.,  falls  to  the  same  temperature  as  the  water. 
At  the  next  stroke  the  entering  steam  finds  cool  metal  to 
come  into  contact  with,  and  is  condensed,  as  we  have  said, 
and  so  onfi  But  the  quantity  condensed  during  the  steam 
stroke  is  precisely  equal  to  that  evaporated  during  the 


114 

exhaust  stroke,  and  consequently  no  condensed  steam  can 
leave  the  engine  as  water. 

Let  us  suppose,  for  the  sake  of  argument,  however,  that 
an  engine  using  20  Ibs.  of  100  Ibs  steam  per  horse  per  hour, 
discharges  two  pounds  of  water  per  horse  per  hour.  As 
each  of  these  brought,  in  round  numbers,  f  185  thermal  units 
into  the  engine,  and  takes  away  only  212  units,  it  is  clear 
that  each  pound  must  leave  behind  it  973  units  ;  conse- 
quently the  cylinder  will  be  hotter  at  the  end  of  each  revolu- 
tion than  it  was  at  the  beginning,  and  the  process  would 
go  on  until  condensation  must  entirely  cease.  It  will  be 
urged,  however,  that  a  steam  jacket  certainly  does  discharge 
water,  and  that  h;  considerable  quantity,  which  it  did  not  re- 
ceive ;  and,  as  this  is  apparently  indisputable,  we  are  here  face 
to  face  with  one  of  tht»  puzzles  to  which  we  have  referred. 
The  fact,  however,  is  in  no  wise  inconsistent  with  what  is  ad- 
vanced, v  If  an  engine  with  an  unjacketed  cylinder  regularly 
receives  water  from  the  boiler,  that  engine  will  discharge 
precisely  an  equal  weight  of  water.  The  liquid  will  pass 
away  in  suspension  in  t  he  exhaust  steam  The  engine  has 
no  power  whatever  of  converting  it  into  steam.  The  case 
of  a  jacketed  engine  is  different.  Such  an  engine  will  evap- 
orate in  the  cylinder  water  received  with  the  steam,  but  it 
can  only  do  so  at  the  expense  of  the  steam  contained  in  the 
jacket.  For  every  i  Ib.  of  water  boiled  away  in  the  cylinder 
I  Ib.  of  steam  is  condensed  in  the  jacket  ;  and  the  corollary 
is  that,  if  an  engine  were  supplied  with  perfectly  dry  steam, 
there  would  be  no  steam  condensed  in  the  jacket,  save  that 
required  to  meet  the  loss  due  to  radiation  and  the  conver- 
sion of  heat  into  work.  The  effect  of  the  jacket  will  be  to 
boil  a  portion  of  the  water  during  the  close  of  the  stroke, 
and  so  to  keep  up  the  toe  of  the  diagram,  and  so  get  more 
work  out  of  the  steam.  If,  however,  the  steam  was  deliv- 
ered wet  to  the  engine,  it  is  very  doubtful  if  the  jacket  could 
be  productive  of  much  economy.  The  water  would  be  con- 
verted into  steam  during  the  exhaust  stroke,  and  no  equiva- 
lent would  be  obtained  for  the  steam  lost  in  the  jacket. 

In  a  good  condensing  engine  about  3  Ibs.  of  steam  per 
horse  per  hour  are  condensed  in  the  jacket.  The  cylinder 
will  use,  say,  15  Ibs.  of  steam,  so  the  total  consumption  is 
1 8  Ibs.  per  horse  per  hour.  It  is  none  the  less  a  fact,  al- 
though it  is  not  generally  known,  that  the  average  Lancashire 
boiler  sends  about  8  per  cent,  of  water  in  the  forif  of  in- 
sensible priming  with  the  steam.  Now,  8  per  cent,  of  1 8 
Ibs.  i's  1.44  Ibs.,  so  that  in  this  way  we  have  nearly  one-half 
the  jacket  condensation  accounted  for  as  just  explained. 


One  horse-power  represents  2,562  thermal  units  expended 
per  hour,  or,  say,  2.6  Ibs.  of  steam  of  100  Ibs.  pressure  con- 
densed to  less  than  atmospheric  pressure;  aiid  1.44— • 
260=  4. 04  Ibs.  per  horse  per  hour,  as  the  necessary  jacket 
condensation,  if  no  water  is  to  be  found  in  the  working 
cylinder  at  the  end  of  each  stroke.  That  this  quantity  is  not 
condensed  only  proves  that  the  water  received  from  the 
boiler,  or  resulting  from  the  performance  of  work,  is  not  all 
re-evaporated. 

Something  still  remains  to  be  written  about  the  true 
action  of  the  steam  jacket,  but  this  we  must  reserve  for  the 
present.  We  have  said  enough,  we  think,  to  show  that,  as 
we  have  stated,  the  jacket  has  more  to  do  than  keep  the 
cylinder  hot.  With  jacketed  engines,  more  than  any  other, 
it  is  essential  that  the  steam  should  be  dry.  In  the  case  of 
an  unjacketed  engine,  water  supplied  from  the  boiler  will 
pass  through  the  engine  as  water,  and  do  little  harm;  but,  if, 
the  engine  is  jacketed,  then  the  whole  or  part  of  this  water 
will  be  converted  into  steam,  especially  during  the  period  of 
exhaust,  when  it  [can  do  more  good  than  if  it  were  boiled 
away  in  a  pot  in  the  engine  room.  This  is  the  principal 
reason  why  such  conflicting  opinions  are  expressed  concern- 
ing the  value  of  jackets.  That  depends  principally  on  the 
merits  of  the  boiler. 

TREATMENT  OF  NEW  BOILERS. 

No  ne-.v  boiler  should  have  pressure  put  upon  it  at  once. 
Instead,  it  should  be  heated  up  slowly  for  the  first  day,  and 
whether  steam  is  wanted  or  not.  Long  before  all  the  joints 
are  made,  or  the  engine  ready  for  steam,  the  boiler  should 
be  set  and  in  working  order.  A  slight  fire  should  be 
made  and  the  water  warmed  up  to  about  blood  heat  only, 
and  left  to  stand  in  that  condition  and  cool  off,  and  absolute 
pressure  should  proceed  by  very  slow  stages.  Persons  who 
set  a  boiler  and  then  build  a  roaring  fire  'under  it,  and  get 
steam  as  soon  as  they  can,  need  not  be  surprised  to  find  a 
great  many  leaks  developed;  even  if  the  boiler  does  not  actu- 
ally and  visibly  leak,  an  enormous  strain  is  needlessly  put 
upon  it  which  cannot  fail  to  injure  it.  Of  all  the  forces  en- 
gineers deal  with,  there  are  none  more  tremendous  than  ex- 
pansion and  contraction. 


COMPARATIVE  ECONOMY  OF  HIGH  AND 
SLOW  SPEED  ENGINES. 

In  nearly  every  case  where  a  flour  mill  is  built,  it  is 
intended  to  be  a  permanent  investment.  The  very  nature  of 
the  milling  business  makes  it  necessary  that  the  plant  shall 
be  built  and  operated,  not  for  one,  two  or  three  years,  but 
for  a  long  term  of  years.  It  is  the  ambition  of  every  mill 
owner,  when  he  builds  a  mill,  to  make  it  the  foundation  of  a 
permanent  business,  and,  if  he  is  wise,  he  will  build  such  a 
mill  and  select  such  machinery  as  will  prove  economical,  not 
in  first  cost,  but  in  the  long  run.  In  no  part,  of  the  milling 
plant  is  this  more  important  than  in  the  power  outfit  of 
steam  mills,  and,  as  most  of  the  mills  now  being  built  are 
steam  mills,  the  comparative  economy  of  different  kinds  of 
steam  engines  becomes  an  important  subject  for  considera- 
tion. No  matter  whether  the  mill  is  large  or  small,  unless 
it  is  so  advantageously  located  as  regards  its  supply  of  fuel 
that  the  cost  is  practically  nothing,  any  wastefulness  in  the 
consumption  of  fuel  creates  a  steady  drain  on  the  earning  of 
the  mill  which  will  seriously  affect  the  balance  of  the  profit 
and  loss  account,  and,  where  fuel  is  expensive,  may  result  in 
transferring  the  balance  to  the  wrong  side  ofthe  account, 

In  selecting  a  power  plant,  it  is  a  mistake,  frequently  made, 
to  consider  the  first  cost  of  the  plant  as  of  the  highest 
importance,  and  any  saving  in  this  direction  as  so  much 
clear  gain.  Especially  is  this  the  case  in  flouring  mills  of 
small  capacity,  where  the  builder's  capital  is  limited,  and 
where  the  idea  is  to  get  as  much  mill  for  as  little  money  as 
possible.  In  such  case,  any  money  borrowed  from  the 
power  plant  to  put  into  the  balance  of  the  mill,  is  bor- 
rowed at  a  ruinously  high  rate  of  interest,  and  it  is,  more- 
over, borrowed  without  any  chance  of  repayment,  except 
by  throwing  out  the  cheap  plant  and  substituting  the 
higher  priced  and  more  economical  one  at  great  expense. 
In  no  way  is  the  miller  more  often  misled  than  by  the 
claims  of  the  builders  of  the  high-speed  automatic  engines, 
where  the  name  automatic  is  relied  upon  to  cover  a  mul- 
titude of  sins  in  the  direction  of  low  economy.  In  this 
connection,  some  facts  from  a  paper  by  J.  A.  Powers  are 
instructive: 

After  carefully  analyzing  the  problem  and  considering 
the    requirements    of    the  load  to   be    driven  in  electric 
lighting  stations,  which  are  more  favorable  for  the    high 
speed  engines  than  is  the  case  in  flouring-mill  work,  Mr. 
Powers  reaches  the  conclusion  as  to  the  different  styles  of 


engines  in  t"he  consumption  of  steam,  as  stated  by  engine 
builders  : 

Steam  per  H.  P.  per  hour. 

High    speed  engines 28  to  32  Ibs 

Corliss  engines,  non-condensing 24  to  ?6  Ibs. 

"  <     "          condensing 20  to  21  Ibs. 

compound  condensing. 15  to  16  Ibs. 

With  an  evaporation  of  eight  pounds  of  water  per 
pound  of  coal,  the  coal  consumption  would  be  as  follows  : 

Coal  per  H.  P.  per  hour. 

High  speed  engine 3.50104       Ibs. 

Corliss  engines,  non-condensing 3       to  3.25  Ibs, 

"         condensing 2.50  to  2.62  Ibs. 

"         compound  condensing 1.87102       Ibs. 

As  the  interest  on  the  first  cost  of  the  steam  plant  should 
properly  be  charged  against  its  economy,  the  following 
statement  of  comparative  first  cost  is  given: 

High  speed  engine $31  to  $36  per  H.  P. 

Corliss  engines,  non-condensing 42  to     46 

condensing 43  to     48 

"  "        compound   condensing 5210    57         " 

The  comparison  of  first  cost  and  fuel  saving  is  as  follows  : 

Coal. 
Cost.  Consumption. 

High  speed  engine 100  per  cent.  100  per  cent. 

Corliss  engine,  non-condensing 131         "  62         " 

"         "         condensing 136         "  56 

"         "        compound   cond'g..   163  44 

If  the  cost  of  coal  is  taken  at  $3  per  ton  and  interest  i> 
figured  at  six  per  cent.,  which  figures  may  be  considered  a 
fair  average,  the  results,  based  on  the  foregoing  figures,  fcr 
a  plant  of  400  horse-power,  will  be  as  follows  : 

Cost  of  Coal  Saving  in  Coal 

per  day.  over  High  Speed. 

High  speed  engine $24.75  $ 

Corliss  engine,  non-condensing. ..        18.90  5.85 

condensing 15-24  9.51 

"  "        com'd  condensing        11.64  13.11 

Interest  Loss  in  Interest 

per  day.  over  High  Sp  eed. 

High  speed  engine $2.36  $.... 

Corliss  engine,  non-condensing 3.08  .72 

condensing 3.15  .79 

"  "         com'd  condensing.         3.75  1.39 

And  the  saving  per  day  over  the  high  speed  engine  is: 

Corliss  engine,  non-condensing $  5.13 

"  "         condensing •'        8.72 

"          "        compound  condensing 1172 

So  far  as  the  steam  consumption  is  concerned,  results  in 
every-day  work  show  that  the  comparison  is  made  as  favor- 


able  as  possible  for  the  high  speed  engine,  for,  while  records 
of  actual  tests  of  Corliss  engines  show  that  the  figures  given 
are  not'understated,  the  average  of  high  speed  engines  after 
running  a  short  time  is  not  nearly  as  low  as  thirty-two 
pounds  per  indicated  horse  power  per  hour.  So  far  as  the 
cost  of  the  respective  plants  are  concerned,  we  should  be 
inclined,  especially  for  small  plants,  to  put  the  average  cost 
of  the  high  speed  plant  a  little  lower  than  that,  of  the  Corliss  a 
little  higher,  but  this  change  would  not  materially  affect  the 
result  so  far  as  comparative  economy  is  concerned. 

To  bring  the  matter  in  shape  to  fairly  apply  to  the 
requirements  of  the  average  100  barrel  mill,  it  may  be  assumed 
that  the  power  required  will  be  50  horse  power.  In  the 
absence  of  exact  data  as  to  the  cost  of  the  high  speed  plant, 
and  to  give  it  as  favorable  a  showing  as  possible,  the  cost  of 
the  respective  plants  may  be  stated  as  follows  : 

High  speed $1,500 

Corliss,  non-condensing 2,700 

condensing 3,200 

"          compound  condensing 4,300 

The  economy  would  then  be  : 

Water  per  Coal  per 

H.  P.  per  hour.  H.  P.  per  hour. 

Highspeed 32  Ibs.  4        Ibs. 

Corliss  non-condensing 26  Ibs.  3.25  Ibs. 

"         condensing 20  Ibs.  2.5     Ibs. 

"         compound  condensing 16  Ibs.  2.       Ibs. 

And  with  coal  and  rate  of  interest  assumed  as  above, 
based  on  a  continuous  run  of  280  days,  24  hours  per  day,  the 
comparison  is  summarized  as  follows  : 
Cost  of 

Fuel  per  Year  Interest.     Total. 

~  High  speed $2,016  $90          $2,106 

Corliss,  non-condensing 1,638  162             1,800 

"         condensing 1,260  192             J,452 

"         comp'd  condensing 1,008  258             1,266 

The  ratio  of  saving  to  difference  in  cost  between  the  high 
speed  plant  and  the  others,  may  be  stated  as  follows  : 

Between  high  speed  and  Corliss  non-condensing,      25     per  cent. 

"  condensing 38^       " 

"  "  comp.condens'g     30  " 

Or,  in  other  words,  it  would  take  four  years  to  save  the 
difference  in  cost  using  the  non-condensing  Corliss,  a  little 
over  two  and  one-half  years  if  condensing,  and  three  and  one- 
half  years  if  compound  condensing.  In  either  case,  the  sav- 
ing would  be  steadily  continued,  long  after  the  cost  of  the 
plan,t  had  been  wiped  out. 


U9 
RULE  FOR  SAFETY  VALVE  WEIGHTS. 

There  seems  to  be  a  steady  demand  for  this  rule.  The 
following  is  an  easily  remembered  formula  which  may  be  of 
service  to  some  : 

D2  X  .7854  X  P— D  W  +  F 

L  =  W* 

Now,  this  looks  somewhat  formidable  to  those  who  are 
not  familiar  with  calculations  in  any  form,  but  a  few  words 
and  a  little  study  will  make  it  clear  to  most  persons.  The 
explanation  is  this : 

D2  means  that  the  diameter  of  the  valve  is  to  be  multi- 
plied by  the  same  figure.  If  the  valve  is  4"  diameter  multi- 
ply it  by  4.  If  it  is  2"  multiply  it  by  2 ;  if  ^y2"  multiply  it 
by  3^.  This  is  called  squaring  the  diameter.  Now  multi- 
ply the  sum  by  .7854  and  observe  the  decimal.  This  gives 
the  area,  as  it  is  called,  or  number  of  square '  inches  in  the 
valve  exposed  to  pressure.  Of  course,  the  end  of  the  valve 
exposed  to  steam  has  been  measured  —  not  the  top  of  it. 
Now  multiply  the  sum  last  found  by  the  pressure  to  be  car- 
ried on  the  boiler,  say  60,  if  it  is  60  pounds.  This  gives  the 
force  pressing  on  the  bottom  of  the  valve  to  blow  it  off  its 
seat.  Take  half  the  weight  of  the  lever  and  whole  weight 
of  valve  and  stem  from  this  last  sum,  and  then  multiply  by 
the  distance  from  the  center  of  the  valve-stem  to  the  center 
of  the  hole  in  the  short  end  of  the  lever.  Divide  the  sum  so 
found  by  the  whole  length  of  the  lever.  Then  you  have  the 
weight  of  the  ball  to  go  on  the  end  to  give  60  Ibs.  per  square 
inch  on  the  boiler. 

This  is,  in  brief,  the  rule ;  but  it  is  of  no  earthly  use  to  those 
who  are  not  familiar  with  ordinary  arithmetic,  for  they  will 
be  very  likely  to  make  serious  errors  in  the  result  by  mis- 
takes in  figuring. 

The  steamboat  inspection  law  demands  that  candidates 
for  marine  licenses  shall  know  this  rule;  but  in  many  cases  it 
would  be  just  as  useful  to  demand  that  a  man  should  be  able 
to  jump  twenty-five  feet  from  a  standstill,  for  those  who  are 
incompetent  can  learn  the  rule  as  above  given,  and  pass  mus- 
ter, without  being  practical  working  engineers,  while  those 
who  have  mathematical  abilities  and  practical  experience 
also,  are  only  affronted  by  such  appeals  to  the  knowledge 
they  have  of  their  calling. 

The  qualifications  and  abilities  of  engineers  for  their 
positions  are  in  nowise  determined  by  such  trifling  exercises 
as  these. 


Amount  of  horse  power  transmitted  by  single  belts  to  pul« 
leys  running  100  revolutions  per  minute  when  the  diameter  of 
the  driving  pulley  is  equal  to  the  diameter  of  the  driven  pulley. 


Diameter 
of 
Pulley. 

WIDTH  OF  BELT  IN  INCHES, 

2 

2^2 

3 

Zl/2   \    4 

4^ 

5 

6 
H.  P. 

In. 

H  P 

H.  P. 

H  P 

H.  P. 

H.  P. 

H.  P 

H.  P 

•44 

•54 

.65 

.76 

.87 

.98 

.09 

•31 

W 

•47 

•59 

•7i 

•83 

•95 

.07 

.19 

.42 

7 

•51 

.64 

.76 

.89 

.01 

.14 

•27 

•53 

rA 

•55 

-68 

.82 

•95 

.09 

•23 

•36 

.64 

8 

•58 

•73 

.87 

.02 

.16 

•31 

•45 

•  75 

8/2 

.62 

'     -77 

•93 

.08 

,24. 

•39 

•55 

.86 

9  , 

•65 

.82 

.98 

•*5 

•31 

.48 

.64 

•97 

9K 

.69 

.86 

.04 

.21 

-391     -56 

•74 

2.08 

10 

•73 

.91 

.09 

.27 

•45 

•63 

.81 

2.18 

ii 

.8 

i. 

.2 

•4 

.6 

.8 

2. 

2.4 

12 

.87 

.09 

•31 

•53 

•75 

•97 

2.18 

2.62 

13 

•95 

.18 

•42 

•65 

.89 

2.12 

2.36 

2.83 

H 

.02 

.27 

•52 

•77 

2.02 

2.27 

2-53 

3-05 

r$ 

.09 

•36 

.64 

.91 

2.19 

2.46 

2-73 

3-29 

16 

.16 

•45 

•74 

2.0^ 

2.32 

2.6l 

2.91 

3-48 

17 

•2* 

•55 

.85 

2.16 

2.47 

2.78 

3-09 

3-70 

18 

•31 

.64 

.96 

2.29 

2.62 

2.95 

3-27 

3-92 

*9 

•39 

•73 

2.07 

2.42 

2.76 

y  1  l 

3-45 

4.14 

20 

•45 

.82 

2.18 

2.55 

2.9I 

3-27 

3-64 

4-36 

21 

•52 

.91 

2.29 

2.67 

3-05 

3-44 

3.82 

4-58 

22 

.6 

2. 

2.4' 

2.8 

3-2 

3-6 

4 

4-8 

23 

.67 

2.09 

2-51 

2-93 

3-35 

3-75 

4.18 

5.02 

24 

3-5 

4-4 

5-2 

7- 

8.7 

10.5 

12.2 

14. 

25 

3-6 

4-5 

5-5 

7-3 

9.1 

10.9 

12.7 

14-5 

26 

3-8 

47 

5-7 

7.6 

9-5 

11.3 

I3.2 

15.1 

27 

3-9 

4.9 

5-9 

7.8 

9.8 

11.8 

*3-7 

15.6 

28 

4.1 

5-i 

6.1 

8.1 

10.2 

12.2 

14-3 

16.3 

29 

4-2 

5-3 

6-3 

8.4 

10.5 

12.6 

14.8 

16.9 

30 

44 

5-4 

6.6 

8.7 

10.9 

I3-I 

15-3 

17.4. 

31 

4-5 

5-6 

6.8 

9- 

"•3 

J3-5 

15.8 

1  8. 

32 

4-7 

5-8 

7- 

9-3 

ii.  6 

14, 

16.3 

18.6 

33 

4.8 

6. 

7-2 

9.6 

12. 

14.4 

16.8 

19.2 

34 

4.9 

6.2 

7-4 

9-9 

12.4 

14.8 

17-3 

19.8 

35 

5-1 

6.4 

7.6 

10.2 

12.7 

!5-3 

17.9 

20.4 

Amount  of  horse  power  transmitted  by  single  belts  to  pul- 
leys running  100  revolutions  per  minute  when  the  diameter  of 
the  driving  wheel  is  equal  to  the  diameter  of  the  driven  pulley. 


Diameter 
of 
Pulley. 

WIDTH  OF  BELT  IN  INCHES. 

2 

2/2 

3 

3/2 

4 

4/2 

5 

6 

In. 

H.  P. 

H.  P. 

H.  P. 

H.  P. 

H.  P. 

H.P. 

H.  P. 

H.  P. 

36 

5-2 

6-5 

7.8 

10.5 

'3-1 

15.7 

18.3 

20.9 

37 

5-4 

6.7 

8.1 

10.8 

13.5 

16.2 

18.9 

21.5 

38 

5-5 

6.9 

8.3 

ii. 

13.8 

16.6 

'9-3 

22.1 

39 

5-7 

7-  l 

8.5 

11.3 

14.2 

17. 

19.9 

22.7 

40 

5-8 

7-3 

8.7 

u.  6 

14.6 

175 

20.4 

23-3 

42 

6.1 

7-6 

9.2 

12.2 

'5-3 

I&2 

21.4 

24.3 

6.4 

8. 

9.6 

12.8 

16. 

19.2 

22.4 

25.6 

46 

6.7 

8.4 

10. 

13.4 

1  6. 

20.1 

23-4 

26.8 

48 

7- 

8.8 

10.4 

14. 

17.4 

21. 

24.4 

28. 

50 

7.2 

9- 

10.9 

14.6 

18.2 

21.8 

25.4 

29. 

54 

7.8 

9.8 

ii.  8 

I5-6 

19.6 

23.6 

26.4 

31.2 

60 

8.8 

10.8 

13.1 

17.4 

21.8 

26.2 

30.6 

34-8 

66 

9.6 

12. 

14.4 

19.2 

24. 

28.8 

33-6 

72 

10.4 

13. 

15.6 

21. 

26.2 

31.4 

36.6 

41.8 

i 

11.4 

12.2 

14-2 
15.2 

17- 

19.4 

22.6 
24.4 

28.4 
30.6 

34- 
36.4 

30.8 
42.8 

45-4 

48.6 

26 

3-8 

4-7 

5-7 

7.6 

9-5 

"•3 

13.2 

15.1 

27 

3-9 

4-9 

5-9 

7.8 

9.8 

H.8 

13-7 

15.6 

28 

4.1 

6.1 

8.1 

10.2 

12.2 

14-3 

16.3 

29 

4.2 

5-3 

6.3 

8.4 

10.5 

12.6 

14.8 

16.9 

30 

4.4 

5-4 

6.6 

8.7 

10.9 

13.1 

15-3 

17.4 

4-5 

5-6 

6.8 

9- 

II.3 

13.5 

15.8 

1  8. 

32 

4-7 

5.8 

7- 

9-3 

ii.  6 

14. 

16.3 

18.6 

33 

4-8 

6. 

7.2 

9.6 

12. 

14.4 

16.8 

19.2 

34 

4.9 

6.2 

7-4 

9-9 

12.4 

14.8 

17.3 

19.8 

35 

6.4 

7.6 

10.2 

12.7 

15-3 

17.9 

20.4 

36 

5-2 

6.5 

7.8 

10.5 

I3.I 

15-7 

18.3 

20.9 

37 

5-4 

6.7 

8.1 

10.8 

13-5 

16.2 

18.9 

21.5 

38 

5-5 

6.9 

8.3 

ii. 

13.8 

16.6 

19-3 

22.1 

39 

5-7 

7.1 

8.5 

11.3 

14.2 

17- 

19.9 

22.7 

40 

5-8 

7-3 

8.7 

u.  6 

14.6 

17-5 

20.4 

23-3 

42 
44 

6.1 
6.4 

7.6 

8. 

9.2 
9.6 

12.2 

12.8 

'I'3 

1  6. 

18.2 
19.2 

21.4 

22.4 

24-3 
25-6 

HOW  TO  TRUE  AN  EMERY  WHEEL. 
An  emery  wheel  may  be  trued  by  using  a  bar  of  rough  iron 
or  copper  as  a  turning  tool. 


122 

HOW  TO  FIND  THE   DIAMETER  OF  HIGH  AND 
LOW  PRESSURE  CYLINDERS  AT  DIF- 
FERENT PRESSURES. 

The  following  is  a  table  from  actual  practice  giving  the 
diameters  of  the  high  and  low  pressure  cylinders  at  different 
boiler  pressures,  the  piston   speed  being  taken  at  420  ft. 
minute : 


Indicated 
horse-power. 

PH     . 

I 

.2   & 

Q 

Boiler  pres- 
sure 45  Ibs. 

Boiler  pres- 
sure 80  Ibs. 

Boiler  pres- 
Isure  125  Ibs. 

Diam.  H.P. 
cylinder. 

Diam.  H.P. 
cylinder. 

Diam.  H.P. 
cylinder. 

10 

20 
25 
3° 
40 

50 

100 

150 

7X  in. 

10 

nX 

I2# 
1* 

16 

22>£ 
27^ 

4      in. 
& 

*>y2 

71/* 
W 
9X 
13 
16 

3^  ^. 

\1A 
6# 

I? 

uX 

H 

3Xin- 
4K 
S'A 

5% 
W 

7X 

10% 

™tt 

THE  LARGEST  STEAM  BOILER  IN  AMERICA. 

The  largest  steam  boiler  ever  constructed  in  America  has 
been  manufactured  at  Scranton,  Pa.  The  boiler  is  35  feet  4 
inches  in  length,  10  feet  6  inches  wide,  and  n  feet  6  inches 
high.  It  is  made  of  steel,  weighs  45  tons,  and  is  of  1,000 
horse-power.  One  sheet  of  steel  used  weighed  two  tons. 
The  metal  from  the  "  crown  sheet "  to  the  "  wagon  top  "  is 
i  y$  inches  in  diameter,  that  near  the  valve  is  ^  of  an  inch, 
and  the  other  parts  9-16  of  an  inch  in  diameter.  There  are 
198  three-inch  tubes  in  the  boiler,  a  double  fire  box  connect- 
ing with  the  flues,  and  stay  bolts  and  rivets  are  used  varying 
in  length  from  six  to  ten  inches. 

HOW  TO  MAKE  A  STRONG  FLANGE  JOINT. 

To  make  a  flange  joint  that  won't  leak  or  burn  out  on 
steam  pipes,  mix  two  parts  white  lead  to  one  part  red  lead  to 
a  stiff  putty  ;  spread  on  the  flange  evenly,  and  cut  a  liner  of 
gauze  wire —  like  mosquito  net  wire —  and  lay  on  the  putty,  of 
course  cutting  out  the  proper  holes ;  then  bring  the  flanges 
*'  fair,"  put  in  the  bolts  and  turn  the  nuts  on  evenly.  For  a 
permanent  joint  this  is  A  i. 


123 
DENSITY  OF  WATER. 


Tempera- 
ture F. 

Comparative 
Volume. 
Water    32°-=:!. 

Comparative 
Density. 
Water    32°=  I. 

Weight  of 
I    Cubic   Foot. 

32 

i  .00000 

.00000 

62.418 

35 

0.99993 

.00007 

62.422 

40 

0.99989 

.ooou 

62.425 

45 

0.99993 

.00007 

62.422 

46 

.00000 

.00000 

62.418 

50 

.00015 

.99985 

62.409 

55 

.00038 

.99961 

62.394 

60 

.00074 

.99926 

62.372 

«5 

.00119 

.99881 

62.344 

70 

.00160 

.99832 

62.313 

75 

.00239 

.99771 

62.275 

80 

.00299 

.99702 

62.232 

85 

.00379 

.99622 

62.182 

90 

.00459 

•99543 

62.133 

95 

.00554 

.99449 

62.074 

100 

.00639 

.99365 

62.022 

105 

.00739 

.99260 

61.960 

no 

.00889 

.99119 

61.868 

"5 

.00989 

.99021 

61.807 

120 

.01139 

.98874 

6i.7i5 

125 

.01239 

.98808 

61.654 

130 

135 

.01390 
•01539 

.98630 
.98484 

61.563 
61.472 

140 

.01690 

.98339 

61.381 

145 

.01839 

.98194 

61.291 

150 

.01989 

.98050 

61.201 

155 

.02164 

.97882 

61.096 

160 

.02340 

.97715 

60.941 

165 

.02589 

-97477 

60.843 

170 

.02690 

.97380 

60  783 

175 

.02906 

.97193 

60.665 

180 

.03100 

.97006 

60.543 

185 

.03300 

.96828 

60.430 

190 

.03500 

.86632 

60.314 

195 

.03700 

.96440 

60.198 

200 

.03889 

.96256 

60.081 

205 

.0414 

.9602 

59-937 

210 

•  0434 

.9584 

59  822 

112 

.0444 

•9575 

59.769 

I24 

CALKING  STEAM  BOILERS. 

No  well-made  boiler  ought  to  require  to  be  heavily  calked, 
and  to  provide  fcfr  light  calking  it  is  imperative  that  the 
plates  of  a  boiler  should  be  effectually  and  thoroughly 
cleaned  of  all  fire  scale  before  being  riveted  up.  Good  boiler 
work  should  be  very  nearly  tight  without  calking,  but  it  is 
difficult  to  attain  this  degree  of  excellence  with  hand  work. 
Hydraulic  riveting,  in  which  the  plates  are  forcibly  pressed 
together  before  the  rivet  is  closed  and  made  to  fit  the  hole, 
will,  if  carefully  done,  be  found  to  give  a  tight  boiler  without 
calking.  It  is  obvious  that  tightness  can  only  be  secured  by 
insuring  metallic  contact.  If  all  the  rivets  fill  the  holes  per- 
fectly, no  leakage  can  percolate  past  the  rivet  heads.  If  any 
rivet  heads  require  calking,  they  should  be  cut  out  and  a 
fresh  rivet  inserted,  as  a  leak  is  a  sure  indication  that  the 
rivet  does  not  fill  the  hole,  and  is  possibly  imperfectly  closed 
in  addition.  It  is  also  obvious  that  to  insure  a  tight  boiler 
the  surfaces  of  the  plates  must  be  in  metallic  contact,  and 
must  remain  so  when  the  boiler  is  subjected  to  the  working 
pressure  which,  with  the  alterations  of  temperature,  will  pro- 
duce certain  inevitable  changes  in  the  form  of  the  boiler.  It 

is  obviously  necessary 
that  the  surfaces  of  the 
plates  should  be  smooth 
in  order  to  insure  metal- 
lic contact,  and  that 
this  cannot  be  attained 
unless  the  scale  covers 
the  plates  completely, 
or  is  wholly  detached. 
As  a  slight  pin-hole  in 
the  magnetic  oxide  with 
which  steel  plates  are 
coated  will  cause  aleak- 
age,  and  under  certain 
circumstances,  set  i|3  a 

F  galvanic   and  corrosive 

IG>  2'  action,  it  is  advisable  to 

wholly  detach  the  scale.  This  is  easily  done  with  iroiv 
pUtes,  but  steel  plates  cannot  be  completely  cleaned  of  mag- 
n£tic  oxide  by  the  usual  mechanical  methods.  An  excellent 
arid  effective  method  is  that  used  at  the  Crewe  Works  of  the 
London  &  Northwestern  Railway  (England).  The  plates 
Are  brushed  over  with  muriatic  acid  diluted  with  water,  and 
Applied  with  a  brush  or  pad  made  with  woolen  waste-  This 


FIG.  i. 


125 

loosens  and  detaches  all  the  scale,  and  the  plates  are  then 
cleaned  by  a  solution  of  lime,  which  effectually  removes  any 
surplus  muriatic  acid.  If  the  plates  are  not  wanted  imme- 
diately, they  can  be  protected  from  rust  by  a  coat  of  turpen- 
tine and  oil.  If  these  precautions  be  not  taken,  the  scale  or 
dirt  upon  the  plates  becomes  crushed  to  powder  by  the 
squeeze  of  the  riveter,  and  a  close  metal  to  metal  joint  is  i  en- 
deied  impossible,  and  the  consequent  leakage  must  be  stopped 
by  calking.  With  clean  plates  much  calking  is  not  neces- 
sary, nor  should  it  be  countenanced,  for,  after  all,  calking  is 
only  an  evidence  of,  and  a  concession  to, 'more  or  less  in- 
ferior, or,  at  least,  imperfect  workmanship. 

Some  boiler-makers  firmly  believe  that  calking  should  be 
performed  both  internally  and  externally,  and  we  may  fre- 
quently hear  this  double  calking  expatiated  upon  as  adding 
to  the  value  of  a  boiler.  As  a  matter  of  fact,  however,  in- 
ternal calking  should  never  be  resorted  to.  By  internal  calk- 
ing we  mean  specially  to  indicate  the  calking  of  edges  ex- 
posed to  steam  or  water,  especially  the  latter,  for  long  expe- 
rience has  shown,  with  very  little  room  for  doubt,  that  internal 
calking  has  frequently  been  either  a  cause  or  an  aid  in  the 
initiation  of  corrosive  channeling  of  the  plates  along  the  line 
of  the  rivet  seams.  Though  channeling  is  commonly  met 
with  along  the  longitudinal  seams,  being  started,  more  fre- 
quently than  by  any  other  cause,  by  the  want  of  perfect  cir- 
cularity of  the  boiler,  yet  it  is  aggravated  by  the  calking  of 
the  edge  of  the  plate  which  borders  the  channeling,  and  the 
explanation  is  that  an  abnormal  stress  is  set  up  in  the  plate 
upon  which  the  calked  edge  is  forced  down,  and  too  fre- 
quently the  calking  toul  itself  is  driven  so  severely  upon  the 
plate  surface  as  to  cause  an  injury  which  develops  as  chan- 
neling when  other  conditions,  such  as  bad  water,  etc.,  are 
present.  These  causes  have  been  mainly  contributory  to  the 
modern  practice  of  outside  calking  only,  and,  with  proper 
workmanship,  this  is  all  that  should  be  required,  but  the  best 
practice  rejects  any  calking  at  all  in  the  strict  acceptation  of 
the  term,  and  demands  that  the  edges  of  the  plates  shall  be 
planed  and  "fullered;"  fullering  being  the  thickening  up  of 
the  whole  edge  of  the  plate  by  means  of  a  tool  having  a  face 
equal  to  the  plate  thickness.  With  such  a  tool  as  this,  it  is 
impossible  to  wedge  apart  the  plates  forming  the  joint,  and 
so  frequently  done  in  the  manner  shown  (exaggerated)  in 
Fig.  i,  when  the  narrow  edge  of  the  calking  tool,  driven  per- 
haps by  a  heavy  hammer,  actually  forces  the  plates  apart  and 
insures  a  tight  joint  only,  by  the  piece  of  damaged  plate  corner 
which  remains  driven  fast  into  the  gap. 


126 

In  contrast  to  this,  Fig.  2  may  be  taken  to  fairly  repre- 
sent the  correct  action  of  the  more  correct  fullering  tool,  the 
plate  edge  being  simply  thickened,  and  contact  between  the 
two  plates  rendered  certain  for  some  distance  in  from  the 
edge.  To  thus  thicken,  or  "  fuller  "  a  plate,  requires  con- 
siderable power,  and  yet,  even  the  use  of  a  more  than  usually 
heavy  hammer  will  not  cause  injury,  as  it  certainly  would  do 
in  careless  hands,  if  used  with  a  narrow  calking  tool.  All 
modern  first-class  boiler  work  in  England  is  inviarably  ful- 
lered, and,  though  the  practice  of  inside  calking  is  still  fol- 
lowed by  firms  who  "  fuller, "  nevertheless,  outside  work  is 
gaining  the  day.  A  further  advantage  of  the  "  fulling  "  tool 
may  be  named.  If  inside  calking  be  still  practiced,  the 
tendency  to  cause  grooving  will  be  less  marked  than  with 
the  narrow  tool,  and  where,  as  at  times,  it  is  absolutely 
necessary  to  internally  calk,  as  may  sometimes  happen,  the 
last  is  a  great  point  in  favor  of  the  broad  tool. 

The  foregoing  remarks  are  suggested  by  a  few  notes  on 
calking  in  an  engineering  work,  wherein  calking  tools  are 
described  as  having  from  y%  to  3-16  of  thickness,  and  "best 
work "  as  being  calked  both  inside  and  out.  In  itself, 
calking  properly  carried  out,  and  lightly  performed  on  good, 
close-riveted  joints,  is  not  necessarily  bad,  but  too  frequently 
is  badly  performed  by  careless  workmen  and  boys,  and  hence 
"  fullering,"  which  is  better  practice,  and  is  also  a  safeguard 
against  carelessness,  is  to  be  preferred  to  the  old  method. 

HOW  TO  THAW  OUT  A  FROZEN  STEAM-PIPE. 
A  good  way  to  thaw  out  a  frozen-up  steam  pipe,  is  to 
take  some  old  cloth,  discarded  clothes,  waste,  old  carpet,  or 
anything  of  that  kind,  and  lay  on  the  pipe  to  be  thawed; 
then  get  some  good  hot  water  and  pour  it  on.  The  cloth 
will  hold  the  heat  on  the  pipe,  and  thaw  it  out  in  five  min- 
utes. This  holds  good  in  any  kind  of  a  freeze,  water-wheel, 
or  anything  else. 

How  many  people,  outside  of  practical  men,  know  that 
steam  is  an  invisible  gas  until  the  moisture  it  bears  is  con- 
densed l.y  contact  with  cold  air.  Such  is  a  fact,  neverthe- 
less, as  we  may  readily  see  by  boiling  water  in  a  glass  vessel. 
The  bubbles  that  rise  to  the  surface  of  the  water  are  appar- 
ently empty —  the  white  vapor  appears  after  they  burst  iiithe 
air  at  the  surface  of  the  water. 


THE  PREVENTION  OF  ACCIDENTS  FROM  RUN* 

NING  MACHINERY. 

A  German  commission  \vas  appointed  to  investigate  acci- 
dents in  mills  and  factories,  and  draw  up  a  series  of  rules  fof 
their  prevention.  Some  of  these  rules  are  as  follows: 

SHAFTING. 

All  work  on  transmissions,  especially  the  cleaning  and 
lubricating  of  shafts,  bearings  and  pulleys,  as  well  as  the* 
binding,  lacing,  shipping  and  unshipping  of  belts,  must  be 
performed  only  by  men  especially  instructed  in,  or  charged 
with,  such  labors.  Females  and  boys  are  not  permitted  to 
do  this  work. 

The  lacing,  binding  or  packing  of  belts,  if  they  lie  upon 
either  shaft  or  pulleys  during  the  operation,  must  be  strictly 
prohibited.  During  the  lacing  and  connecting  of  belts, 
strict  attention  is  to  be  paid  to  their  removal  from  revolv- 
ing parts,  either  by  hanging  them  upon  a  hook  fastened  to 
the  ceiling,  or  in  any  other  practical  manner;  the  same 
applies  to  smaller  belts,  which  are  occasionally  unshipped 
and  run  idle. 

While  the  shafts  are  in  motion,  they  are  to  be  lubricated, 
or  the  lubricating  devices  examined  only  when  observing  the 
following  rules:  a.  The  person  performing  this  labor  must 
either  do  it  while  standing  upon  the  floor,  or  by  the  use  of  b. 
Firmly  located  stands  or  steps,  especially  constructed  for  the 
purpose,  so  as  to  afford  a  good  and  substantial  footing  to  the 
workman,  c.  Firmly  constructed  sliding  ladders,  running 
on  bars.  d.  Sufficiently  'high  and  strong  ladders,  especially 
constructed  for  this  purpose,  which,  by  appropriate  safe- 
guards (hooks  above  or  iron  points  below),  afford  security 
against  slipping. 

The  cleaning  and  dusting  of  shafts,  as  well  as  of  belt  or 
rope  pulleys  mounted  upon  them,  is  to  be  performed  only 
when  they  are  in  motion,  either  while  the  workman  is 
standing :  #,  on  the  floor  ;  or  £,  on  a  substantially  con- 
structed stage  or  steps ;  in  either  case,  moreover,  only  by 
the  use  of  suitable  cleaning  implements  (duster,  brush,  etc.), 
provided  with  a  handle  of  suitable  length.  The  cleaning  of 
shaft  bearings,  which  can  be  done  either  while  standing  upon 
the  floor  or  by  the  use  of  the  safeguards  mentioned  above, 
must  be  done  only  by  the  use  of  long-handled  implements. 
The  cleaning  of  the  shafts,  while  in  motion,  with  cleaning 
waste  or  rags  held  in  the  hand,  is  to  be  strictly  prohibited., 

All  shaft -bearings  are  to  be  provided  with  automatic 
Imbricating  apparatus. 


Only  after  the  engineer  has  given  the  well  understood 
signal,  plainly  audible  in  the  work-rooms,  is  the  motive  en- 
gine to  be  started.  A  similar  signal  shall  also  be  given  to 
a  certain  number  of  work-rooms,  if  only  their  part  of  the 
machinery  is  to  be  set  in  motion. 

If  any  work  other  than  the  lubricating  and  cleaning  of 
the  shafting  is  to  be  performed  while  the  motive  engine  is 
standing  idle,  the  engineer  is  to  be  notified  of  it,  and  in  what 
Toom  or  place  such  work  is  going  on,  and  he  must  then  allow 
the  engine  to  remain  idle  until  he  has  been  informed  by 
proper  parties  that  the  work  is  finished. 

Plainly  visible  and  easily  accessible  alarm  apparatus  shall 
be  located  at  proper  places  in  the  work-rooms,  to  be  used  in 
cases  of  accident  to  signal  to  the  engineer  to  stop  the 
motive  engine  at  once.  This  alarm  apparatus  shall  always 
be  in  working  order,  and  of  such  a  nature  that  a  plainly 
audible  and  easily  understood  alarm  can  at  once  be  sent  to 
the  engineer  in  charge. 

All  projecting  wedges,  keys,  set-screws,  nuts,  grooves,  or 
other  parts  of  machinery,  having  sharp  edges,  shall  be  sub- 
stantially covered. 

All  belts  and  ropes  which  pass  from  the  shafting  of  one 
story  to  that  of  another  shall  be  guarded  by  fencing  or 
casing  of  wood,  sheet -iron  or  wire  netting  four  feet  six 
inches  high. 

The  belts  passing  from  shafting  in  the  story  under- 
neath and  actuating  machinery  in  the  room  overhead, 
thereby  passing  through  the  ceiling,  must  be  inclosed  with 
proper  casing  or  netting  corresponding  in  height  from  the 
flooi  to  the  construction  of  the  machine.  When  the  ^on- 
strucHon  of  the  machine  does  not  admit  of  the  introduction 
of  c&sing,  then,  at  least,  the  opening  in  the  floor  through 
which  the  belt  or  rope  passes  should  be  inclosed  with  a 
low  casing  at  least  four  inches  high. 

Fix  xl  shafts,  as  well  as  ordinary  shafts,  pulleys  and  fly- 
wheels, running  at  a  little  height  above  the  floor,  and  being 
within  the  locality  where  work  is  performed,  shall  be  securely 
covered. 

These  rules  and  regulations,  intended  as  preventions  of 
accidents  to  workmen,  are  to  be  made  known  by  being  con- 
spicuously posted  in  all  localities  where  labor  is  performed. 

ENGINEERS. 

The  attendant  of  a  motive  engine  is  responsible  for  the 
preservation  and  cleaning  of  the  engine,  as  well  as  the  floor 
of  the  engine-room.  The  minute  inspection  and  lubrication 


I29 

of  the  several  parts  of  the  engine  is  to  be  done  before  it  is 
set  in  motion.  If  any  irregularities  are  observed  during  the 
performance  of  the  engine,  it  is  to  be  stopped  at  once,  and 
the  proper  person  informed  of  the  reason. 

The  tightening  of  wedges,  keys,  nuts,  etc.,  of  revolving 
or  working  part^,  is  to  be  avoided  as  much  as  possible  during 
the  motion  of  the  engine. 

When  large  motive  engines  are  required  to  be  turned 
over  the  dead  point  by  manual  labor,  the  steam  supply  valve 
is  to  be  shut  off. 

After  stoppage,  either  for  rest  or  other  cause,  the  engine 
is  to  be  started  only  after  .a  well-understood  and  plainly 
audible  signal  has  been  given.  The  engineer  must  stop  his 
engine  at  once  upon  receipt  of  an  alarm  signal. 

The  engineer  has  the  efficient  illumination  of  the  engine- 
room,  and  especially  the  parts  moved  by  the  engine,  under  his 
charge. 

The  engineer  must  strictly  forbid  the  entrance  of  unau- 
thorized persons  into  the  engine-room. 

An  attendant  of  a  steam  or  other  power  motor,  who  is 
charged  with  the  supervision  of  the  engine  as  his  only  duty, 
is  permitted  to  leave  his  post  only  after  he  has  turned  the 
care  of  the  engine  over  to  the  person  relieving  him  in  the 
discharge  of  his  duties. 

The  engineer  is  charged  with  the  proper  preservation  of 
his  engine,  and  means  therefor.  He  must  at  once  inform 
his  superior  of  any  defect  noticed  by  him. 

The  engineer  on  duty  is  permitted  only  to  wear  closely 
fitting  and  buttoned  garments.  The  wearing  of  aprons  or 
neckties  with  loose,  fluttering  ends,  is  strictly  prohibited. 

GEARING, 

Every  work  on  gearing,  such  as  cleaning  and  lubricating 
shafts,  bearings,  journals,  pulleys  and  belts,  as  well  as  the 
tying,  lacing  and  shipping  of  the  latter,  is  to  be  performed 
only  by  persons  either  skilled  in  such  work,  or  charged  with 
doing  it.  Females  and  children  are  absolutely  prohibited 
from  doing  such  work. 

When  lacing,  binding  or  repairing  the  belts,  they  must 
either  be  taken  down  altogether  from  the  revolving  shaft  or 
pulley,  or  be  kept  clear  of  them  in  an  appropriate  manner. 
Belts  unshipped  for  other  reasons  are  to  be  treated  in  the 
same  manner. 

The  lubricating  of  bearings  and  the  inspection  of  lubri- 
cating apparatus  must,  when  the  shafting  is  in  motion,  be 
performed  either  while  standing  upon  the  floor- or  by  the  use 


of  steps  or  ladders,  specially  adapted  for  this  purpose,  or 
proper  staging  or  sliding  ladders.  The  lubrication  of 
wheel  work  and  the  greasing  ol  belts  and  ropes  with  solid 
lubricants  is  absolutely  prohibited  during  the  motion  of  the 
parts. 

In  case  of  accident,  any  workman  is  authorized  to  sound 
the  alarm  signal  at  once  by  the  use  of  the  apparatus 
located  in  the  room  for  this  purpose,  to  the  engineer  in 
charge. 

The  following  rules,  classified  under  proper  sub-heads, 
are  published  by  the  Technische  Verein^  at  Augsburg: 

TO    PREVENT   ACCIDENT   BY   THE   SHAFTING. 

While  the  shafts  are  in  motion,  51  IB  strictly  prohibited: 
a.  To  approach  them  with  waste  or  rags,  in  order  to  clean 
them.  b.  In  order  to  clean  them,  to  raise  above  the  floor 
by  means  of  a  ladder  or  other  convenience. 

It  is  allowable  to  clean  the  shafting  and  pulleys  only  while 
in  motion. 

These  parts  of  the  machinery  must  be  cleaned  by  means 
.:f  a  long-handled  brush  only,  and  while  standing  upon  the 
floor. 

The  workmen  charged  with  these  or  other  functions 
about  the  shafting  must  wear  jackets  with  tight  sleeves,  and 
closely  buttoned  up ;  they  must  wear  neither  aprons  nor 
neckties  with  loose  ends. 

Driving  pulleys,  couplings  and  bearings  are  to  be  cleaned 
only  when  at  rest. 

This  labor  should,  in  general,  be  performed  only  after  the 
close  of  the  day's  work.  If  performed  during  the  time  of 
an  accidental  idleness  of  the  machinery,  or  during  the  time 
of  rest,  or  in  the  morning  before  the  commencement  of 
work,  the  engineer  in  charge  is  to  be  informed. 

HOW  TO  FIND  THE  HORSE-POVER  OF  AN 
ENGINE. 

Multiply  the  square  of  the  diameter  of  the  cylinder  by 
0.7854,  and,  if  the  cut-off  is  not  known,  multiply  the  product 
by  four-fifths  of  the  boiler  pressure;  multiply  the  last 
product  by  the  speed  of  the  piston  in  feet  per  minute  (or 
twice  the  stroke  in  feet  and  decimals,  multiplied  by  the  revo- 
lutions per  minute).  Divide  the  final  product  by  33.^00. 
and  the  horse-power  will  be  the  answer. 


ECONOMY  IN  THE  USE  OF  AN  INJECTOR. 

The  following  is  an  interesting  discussion  of  the  economy 
due  to  the  use  of  an  injector,  in  comparison  with  a  direct- 
acting  steam-pump,  both  with  and  without  a  feed-water 
heater,  and  a  geared  pump  with  heater.  Although  the  in- 
vestigation is  theoretical,  it  seems  to  be  based  on  reliable 
data,  so  that  the  results,  as  summarized  in  the  following 
table,  differ  little,  in  all  probability,  from  the  figures  which 
would  be  obtained  by  actual  experiment  : 


Manner    of   feeding 
boiler. 

Temperature     Relative    amount 

Per  cent,  of 

of  Jeed- 

of  coal  required 

fuel  saved 

water. 

for  feed 

over  first 

Fahrenheit. 

apparatus,    in 

case. 

equal  times. 

i. 

D  ir  ec  t-  acting  ) 
steam-pump,    V 

600 

IOO 

o. 

no  heater  ) 

'2. 

Injector,  no  heater 

150  o 

98-5 

1  -5 

3- 

Injector,     w  i  t  h  1 
heater                 \ 

2OO  0 

93-8 

6.2 

4- 

D  irec  t-  acting  | 

steam-pump,    V 

2OO  0 

87.9 

12.  I 

with  heater.  .  .  j 

5- 

Ge  a  red-pump,  ) 

a  c  t  u  ated   by  | 

* 

the   main    en-  }• 

2000 

86.8 

13-3 

gi  n  e  ,   with] 

heater  J 

This  does  not  make  the  comparison  between  the  eco- 
nomical performance  of  an  injector  and  pump  actuated  by 
the  main  engine,  wi'.hout  heater  in  each  case,  or,  in  other 
words,  he  does  not  consider  one  of  the  most  general  divisions 
of  the  problem.  Some  experiments  made  on  the  Illinois 
Central  Railroad  may  be  briefly  cited  to  supplement  the  dis- 
cussion. The  figures  given  represent  averages  of  eight  trips 
of  128  miles  in  each  case  : 


Pounds  of  coal  per  trip.  . . 
Pounds  of  water  per  trip. 
Pounds    of    water  evapo- 
rated per  pound  of  coal 


Feeding 

with 
pump. 

9,529 

4S:SS8 

5.14 


Feeding 

with 

injector. 

8,736 

46,826 


Per  cent, 
of  grain 
for  injector 
9.08 
4.04 


5.26  4.28 


In  the  experiments  with  pump,  the  trains  were  slightly 
heavier  than  when  the  injector  \vas  used,  and  more  time  was 


132 

lost  in  switching  and  standing,  for  which  reason  the  experi- 
menters considered  that  the  economy  of  coal  consumption 
for  the  injector  should  be  reduced  from  9.08  to  6.21  per  cent. 
Some  incidental  advantages  were  observed  in  the  case  of  the 
injector,  the  boiler  steamed  more  freely,  and  there  was  less 
variation  of  pressure. 

TELEPHONES. 

Telephones  are  of  two  kinds— magneto  and  electric.  In  one 
sense  of  the  word  they  both  work  on  the  same  principle. 
namely:  A  series  of  pulsations,  corresponding  in  length  and 


SECTION  OF  A  BLAKE  TRANSMITTER 

strength  to  the  sound  waves  made  by  the  voice,  cause  simi- 
lar pulsations  in  the  receiving  end  of  the  telephone  circuit, 
and  these  pulsations  in  turn  make  sound  waves  which  reach 
the  ear.  Magnetism  and  electricity  work  together  in  a  tele- 
phone. If  a  wire  is  moved  just  in  front  of  the  poles  of  a 
magnet,  whether  it  be  an  electro  or  a  permanent  magnet,  a 
current  of  electricity  is  induced  in  the  wire.  If  a  current  of 
electricity  is  set  to  flowing  around  a  piece  of  soft  iron,  that 


133 

piece  of  iron  becomes  an  .electro-magnet  and  remains  as  such 
as  long  as  the  electricity  flows  around  it.  A  steel  magnet, 
however,  is  always  a  mnguet  unless  particular  pains  are 
taken  to  de-magnetize  it.  Around  every  magnet  is  a  mag- 
netic field,  and  the  iield  is  traversed  by  what  are  known  as 
lines  of  force.  Any  change  in  the  lines  of  force  induce  elec- 
tricity, and  this  is  the  bottom  principle  in  the  working  part 
of  a  telephone.  In  the  receiver  of  a  telephone  of  the  Bell  pat- 


SECTION  OF  A   BELL  RECEIVER. 

tern  is  a  bar  or  straight  permanent  magnet.  At  one  end  of 
this  bar-magnet  is  an  electro-magnet.  Two  small  copper 
wives  lead  back  from  the  electro-magnet  to  the  closed  end  of 
the  receiver  and  the  diaphragm  of  the  telephone  fits  into  the 
case  so  near  the  poles  of  the  electro-magnet  as  to  almost 
touch  it.  This  is  a  magneto-telephone,  and  such  telephones 
are  usually  used  as  receivers.  When  the  diaphragm  is 
moved  back  and  forth  by  sound  waves,  it  cuts  the  lines  of 
force  in  the  magnetic  field  and  induces  undulatory  currents 


134 

of  electricity,  which  are  transmitted  by  the  telephone  wire 
to  the  other  telephone.  In  practice,  ho-vever,  the  imdulatory 
currents  are  induced  by  the  transmitter  which  is  an  electric 
telephone.  The  most  common  type  of  transmitter  in  the 
United  States  is  the  Blake.  In  this  transmitter  the  working 
parts  are  the  diaphragm;  touching  it  is  a  platinum  bottom 
which  in  turn  rests  lightly  against  a  carbon  button.  The 
current  of  electricity  flows  through  the  carbon  button,  then 
through  the  platinum  bottom  and  so  out  to  the  wires.  When 
the  diagraphragm,  vibrating  on  account  of  the  sound  waves 
of  the  voice,  presses  against  the  platinum*  bottom,  it  in  turn 
presses  against  the  carbon  button  giving  it  a  succession  of 
little  squeezes  which  make  the  current  of  electricity  stronger 
or  weaker,  thus  producing  an  unduiatory  current.  The  un- 
dulations carried  over  the  wires  affect  the  magnet  in  the  re- 
ceiving telephone,  causing  the  diaphragm  to  respond,  thus 
reproducing  speech  at  that  end  of  the  telephone  circuit. 

RAPID  KAILWAY  TRANSIT. 

As  an  illustration  of  the  speed  at  which  railway  traveling 
can  be  effected  wnen  the  necessity  arises,  it  may  be  mentioned 
that  an  American  having  missed  the  train  in  London,  and 
having  to  catch  an  Atlantic  steamer  at  Liverpool,  proceeded 
by  the  ordinary  train  to  Crewe,  where  a  special  engine  had 
been  chartered  to  convey  him  direct  to  Liverpool.  The  dis- 
tance between  Crewe  and  Liverpool  is  36  miles,  and  one  of 
the  large  Crewe  engines  completed  the  journey  in  33  min- 
utes, reaching  the  landing  stage  at  Liverpool  10  minutes 
before  the  timed  departure  of  his  steamer. 

USEFUL  CEMENTS. 

A  cement  said  to  resist  petroleum  is  made  by  taking  three 
parts  resin,  one  part  caustic  soda  to  five  of  water,  boiled  to- 
gether, the  resin  being  melted  first,  of  course.  This  makes  a 
resin  soap,  to  which  must  be  added  half  its  weigh  of  plaster. 
It  hardens  in  forty  minute;?.  Useful  for  uniting  lamp  tops 
to  glass.  Glycerine  and  litharge,  mixed  thoroughly,  is  said 
to  form  a  cement  which  hardens  rapidly,  and  will  join  iron 
to  iron  or  iron  to  stone.  Not  affected  by  water  or  acids. 

A  cement  for  leaky  roofs  is  made  by  the  following  articles 


in  the  proportions  named: -4  pounds  resin,  i  pint  linseed  oil, 
2  ounces  red  lead;  stir  in  finest  white  sand  until  of  the 
proper  consistency,  and  apply  hot.  It  possesses  elasticity, 
and  is  fireproof. 

Starch  and  chloride  of  zinc  form  a  cement  which  hardens 
quickly,  and  is  durable.  Sometimes  used  for  stopping  blow- 
holes in  castings. 

A  cement  for  uniting  metal  to  glass  is  made  with  2  ounces 
thick  solution  of  glue,  i  ounce  linseed  oil  varnish.  Stir  and 
boil  thoroughly.  The  pieces  should  be  tied  togeth""'  for 
three  days. 

A  cement  of  100  parts  each  white  sand,  litharge  ,.nd 
limestone,  combined  with  7  parts  of  linseed  oil,  makes  the 
strongest  mineral  cement  known.  At  first  the  mass  is  soft 
and  of  little  coherence,  but  in  six  months'  time  it  will,  if 
pressed,  become  so  hard  as  to  strike  fire  from  steel. 

A  free  application  of  soft  soap  to  a  fresh  burn  almost 
instantly  removes  the  fire  from  the  flesh.  If  the  injury  is 
very  severe,  as  soon  as  the  pain  ceases  apply  linseed  oil,  and 
then  dust  over  with  fine  flour.  When  this  covering  dries 
hard,  repeat  the  oil  and  flour  dressing  until  a  good  coating  is 
obtained.  When  the  latter  dries,  allow  it  to  stand  until  it 
cracks  and  falls  off,  as  it  will  in  a  day  or  two,  and  a  new  skin 
will  be  found  to  have  formed  where  the  skin  was  burned. 

A  new  form  of  electrical  railway  is  being  erected  at  St. 
Paul,  Minn.  The  cars  do  not  touch  the  ground,  but  are 
suspended  from  girders  which  form  the  track  and  at  the 
same  time  the  mains  conveying  the  current.  Speeds  of  from 
eight  to  ten  miles  per  hour  are  expected. 

CELLULOID    SHEATHING. 

Among  the  various  uses  of  celluloid,  it  would  appear  to 
be  a  suitable  sheathing  for  ships,  in  place  of  copper.  A 
French  company  now  undertakes  to  supply  the  substance  for 
this  at  nine  francs  p^r  surface  meter,  and  per  millimeter  of 
thickness.  In  experim  -,its  by  M.  Butaine,  plates  of  celluloid 
applied  to  various  v?s-e!s  in  January  last,  were  removed  fivft 
or  six  months  after  a  id  found  quite  intact  and  free  from 
marine  vegetation,  \\hich  was  abundant  on  parts  uncovered. 
The  color  of  the  .substance  is  indestructible;  the  thickness 
may  be  reduced  to  o  0003  meter;  and  the  qualities  of  elas- 
ticity, solidi'y  and  impevmeability,  resistance  to  chemical 
action,  etc  ,  a  c>  a  1  in  favor  of  the  use  of  celluloid. 


13* 

TRANSMITTING   POWER  BY  A  VACUUM. 

The  idea  of  producing  a  vacuum  in  a  receiver  or  in  a  sys- 
tem of  pipes,  and  utilizing  this  vacuum  to  transmit  power, 
was  put  forth  many  years  ago.  In  an  article  published  in 
1688  Papin  recommends  the  use  of  this  mode  of  transmission. 
He  mentions  its  advantages,  particularly  its  simplicity  and 
convenience  ;  he  gives  for  different  cases,  the  proper  diameters 
of  the  pipes  in  which  the  vacuum  is  made,  and  recommends 
lead  as  the  material  from  which  to  make  them.  The  idea  is 
therefore  old,  but  it  is  only  recently  that  it  has  been  put  into 
practice.  There  is  now  a  central  station  running  on  this  prin- 
ciple in  Paris,  distributing  250  h.  p.  by  means  of  pipes  in 
which  a  seventy-five  per  cent,  vacuum  is  maintained.  One 
year  ago  the  company  running  this  station  had  fifty  custom- 
ers ;  now  there  are  105  leases  signed. 

The  possibility  of  maintaining  a  vacuum  in  an  extensive 
system  of  pipes  has  sometimes  been  questioned.  Repeated 
experiments,  however,  have  shown  that  in  a  line  of  pipes  a 
third  <  f  a  mile  long  a  pressure  of  a  quarter  of  an  atmosphere 
can  be  maintained  so  that  two  gauges,  one  at  each  end  of  the 
pipe,  stand  at  exactly  the  same  point. 

In  the  station  at  Paris  the  exhauster  is  operated  by  a 
Corliss  engine  of  special  construction,  the  speed  of  which  is 
automatically  controlled  by  a  regulator  operated  by  the 
variations  in  pressure  in  the  main  pipe.  The  branch  pipes  are 
of  lead,  and  are  of  different  diameters,  according  to  the  num- 
ber of  consumers  that  each  is  to  supply.  Each  of  these  branch 
pipes  is  provided  with  a  cock  that  can  be  opened  or  closed  by 
means  of  a  wrench  that  is  kept  at  the  central  station.  The 
smaller  branches  that  supply  the  individua1  ruc  "omers  are  also 
of  lead,  and  are  likewise  provided  wich  o  cks  that  can  be 
opened  or  closed  only  by  the  employes  of  tne  company,  who 
retain  possession  of  the  wrenches  that  open  them. 

Two  kinds  of  motors  are  in  use,  one,  the  rotary  class, 
being  used  for  the  smaller  powers;  the  other  class,  which  have 
cylinders  and  pistons,  being  used  only  for  larger  powers.  The 
small  motors  have  an  efficiency  of  about  40  per  cent.,  while 
in  the  largest  size  the  efficiency  is  said  to  be  as  high  as  80  per 
cent. 

SPONTANEOUS  COMBUSTION. 

No  one  of  average  intelligence  and  information  now 
believes  in  the  possibility  of  human  beings  or  the  lower  ani- 
mals undergoing  spontaneous  combustion ;  and  yet  it  is 
barely  forty  years  since  Liebig  devoted  a  long  chapter  of  his 


137 

celebrated  "  Familiar  Letters  on  Chemistry  "  to  exposing  the 
fallacy  of  this  idea,  thus  showing  that  at  that  date  it  was  preva- 
lent. Every  reader  of  Dickens  will  remember  that  in  one  of 
his  most  interesting  stories  an  important  episode  is  made  to 
turn  on  the  popular  belief  in  spontaneous  combustion,  a  belief 
which  Dickens  himself  would  seem  to  have  shared.  Of 
course,  as  Liebig  points  out,  it  requires  no  explanation 
to  account  for  the  connection  which  has  often  been  shown 
to  exist  between  death  by  burning  and  the  too  frequent  indul- 
gence of  ardent  spirits.  Spontaneous  combustion,  though 
not  of  living  animals,  may,  however,  occur  in  certain  cases, 
and  give  rise  to  fires  in  buildings,  etc.,  and  it  may,  therefore, 
be  of  interest  to  the  reader  to  examine  shortly  some  of  those 
possible  cases  and  their  causes.  But  first  of  all,  a  few  words 
as  to  "  combustion "  itself,  the  true  nature  of  which  was 
explained  by  the  famous  French  chemist  Lavoisier,  toward  the 
end  of  last  century. 

An  act  of  combustion  is  an  act  of  chemical  combina- 
tion attended  by  the  evolution  of  heat  and  light,  and,  for  such 
an  act,  two  conditions  are  necessary,  viz.  :  (i)  There  must 
be  a  gas  in  which  the  given  substance  will  burn,  /'.  e.  with 
which  it  will  combine  chemically,  and  (2)  there  must  be  a 
certain  temperature,  the  degree  of  temperature  being  different 
for  each  different  substance.  Thus,  to  take  only  one  common 
example,  a  piece  of  coal  will  remain  unaltered,  at  the  ordi- 
nary temperature  of  the  air,  for  practically  an  unlimited 
period  of  time;  but,  if  it  be  heated  to  a  sufficiently  high 
temperature,  it  will  burn.  /.  e. ,  the  carbon  of  wrhich  it  is  com- 
posed will  combine  with  the  oxygen  of  the  air,  to  form  car- 
bonic acid  gas;  chemical  combination  goes  on  in  this  case 
so  rapidly,  comparatively  speaking,  that  the  heat  and  light 
set  free  by  it  are  palpable  to  our  senses.  Now,  the  two 
requisite  conditions  just  mentioned  sometimes  occur  together 
in  nature,  giving  rise  to  true  cases  of  spontaneous  combustion, 
of  which  the  following  examples  may  be  cited : 

1.  The  ignis  fatmiS)  or  "will-o'-the-wisp,"   is  the  effect 
of  the  spontaneous  ignition  of  a  volatile  compound  of  phos- 
phorus and  hydrogen,  which  is  generated,  under  certain  con- 
ditions,  from  decomposing    animal    and    vegetable   matter. 
This  compound  has  such  an  intense  affinity  for  the  oxygen  of 
the  air,  that,  ihe  moment  it  comes  in  contact  with  ihe  latter, 
it  ignites  of  itself,  giving  out  the  flash  of  light  that  has  de- 
luded so  many  a  wanderer. 

2.  Spontaneous  combustion  also  occurs  not  unfrequently 
in  coal  ships,  or  in  the  coal  bunkers  of  ordinary  vessels.    Coal 
generally  contains  iron  pyrites  or  "  coal  brasses  "  disseminated 


138 

through  it,  and  this  pyrites,  which  is  a  compound  of  iron  and 
sulphur,  has  a  great  tendency  to  absorb  oxygen  from  the  air 
and  to  combine  with  it,  forming  sulphate  of  iron,  or  "  green 
vitriol."  This  absorption  and  combination  are  accompanied 
by  a  rise  of  temperature,  and  they  sometimes  go  on  so  rapidly 
as  to  raise  the  temperature  of  the  mass  sufficiently  high  to 
cause  the  coal  to  catch,  fire. 

3.  Fires  in  buildings  are  often  to  be  traced  to  the  presence 
of  heaps  of  old  cotton  waste.      Such  waste  is  always  more  or 
less  impregnated  with  oil,  and,  being  very  loose  in  texture,  it 
exposes  a  large  surface  to  the  air.     The  result  is  that  the  oil 
rapidly  absorbs  and  combines  chemically  with  the  oxygen  of 
the  air,  just  as  the  pyrites  in  coal  does,  raising  the  temperature 
to  such  a  degree  that  a  fire  ensues. 

4.  The  "  heating  of  corn  which  has  been  stacked  before 
the  sheaves  have  been  sufficiently  dried,  and  which   sometimes 
ends  in  the  corn  stack  catching  fire,  is  the  result  of  chemical 
changes  of  the  nature  of  fermentation. 

5.  Every  one  must  have  observed  what  a  large  amount 
of  heat  is  set  free  when  lime  is  slacked  —  so  much,  indeed, 
that  fires  have  frequently  been  known  to  result  from  it.     The 
reason  of  this  is,  that  the  lime  combines  with  a  certain  pro- 
portion of  water,  this  act  of  combination  causing  much  heat 
Vo  be  liberated. 

The  above  instances  are  sufficient  to  show  that  sponta- 
neous combustion  in  no  way  differs  from  ordinary  combustion, 
excepting  in  that  the  requisite  temperature  is  attained  by 
natural  causes,  and  not  artificially,  and  that  the  old  idea  held 
by  the  superstitions  of  last  century,  that  the  spontaneous 
combustion  of  animals  (which  we  now  know  to  be  impossi- 
ble) was  caused  by  a  peculiar  kind  of  fire,  differing  from  ordi- 
nary fire,  and  not  extinguishable  by  water,  \\as  the  result  of 
ignorance.  There  is  still  one  other  cause  of  spontaneous 
combustion,  often  very  dangerous  in  its  effects,  and  which 
leads  us  on  to  the  subject  of  explosions,  which  must  be  men- 
tioned here.  One  occasionally  reads  in  the  newspapers  of 
explosions  occurring  in  flour  mills,  sometimes  from  no  appar- 
ent cause.  These  explosions  are  cases  of  rapid  sponta- 
neous combustion,  in  which  a  spark  from  the  grindstone  sets 
fire  to  the  fine  flour  dust  with  which  the  air  of  the  mill  is 
impregnated. 

But  what  is  an  "explosion"?  An  explosion  is  nothing 
more  nor  less  than  a  combustion  which  spreads  with  great 
rapidity  throughout  the  whole  mass  of  the  combustible  matter. 
To  our  senses  it  appears  to  be  instantaneous,  but  it  is  not  really 
so.  An  example  \viil  make  this  clear.  A  mixture  of  hydrogen 


339 

and  oxygeii,  or  hydrogen  and  air,  is  a  highly  dangerous  one, 
because  the  instant  that  a  light  is  introduced  into  it  it  explodes ; 
that  is  to  say,  the  particles  of  hydrogen  and  oxygen  in  the 
immediate  neighborhood  of  the  flame  are  raised  to  the  requisite 
temperature  at  which  chemical  combination  can  take  place 
between  them.  They  therefore  do  combine  to  form  water 
vapor,  and,  by  doing  so,  give  out  heat  enough  to  cause  com- 
bination between  the  particles  next  to  them,  and  so  on 
throughout  the  whole  mass  of  the  gas.  This  action  goes  on, 
as  already  stated,  so  rapidly  as  to  be  practically  instantaneous. 
The  terrible  effects  of  explosions  are  caused,  then,  by  the 
sudden  production  of  immense  quantities  of  hot  gases.  '  The 
newspapers  constantly  tell  us  of  disastrous  explosions  resulting 
from  the  bringing  of  a  light  into  a  room  in  which  an  escape  of 
gas  is  going  on.  A  mixture  of  coal  gas  and  air  behaves 
in  precisely  the  same  manner  as  the  mixture  of  hydrogen 
and  oxygen,  or  hydrogen  and  air,  mentioned  above,  with 
the  exception  that  the  products  of  the  combustion  or  ex- 
plosion are  different.  When  an  escape  of  gas  is  suspected,  all 
lights  should  be  rigorously  excluded,  the  gas  turned  off  at  the 
meter  or  main,  and  windows  and  doors  opened,  so  as  to  get 
rid  of  the  already-escaped  gas  as  quickly  as  possible  ;  and  only 
then,  after  complete  ventilation  has  taken  place,  may  a  light 
be  brought  into  the  room  with  safety.  It  is  to  be  hoped  that 
such  a  technical  instruction  bill  will  soon  be  passed  by  parlia- 
ment as  will  render  avoidable  accidents  of  this  nature  less  and 
less  likely  to  occur.  It  is  likewise  a  dangerous  thing  to  blow  out 
aparaffine  lamp  instead  of  turning  the  wick  down,  as,  by  blow- 
ing the  flame  downward,  one  is  apt  to  ignite  the  mixture  of 
oil,  gas  and  air  which  is  in  the  upper  portion  of  the  oil  reser- 
voir, and  so  to  produce  a  serious  explosion. 

The  explosion  caused  by  the  ignition  of  gunpowder  or  any 
other  ordinary  explosive,  is  explicable  in  the  same  way,  but 
can  only  be  touched  upon  in  this  article.  Gunpowder  is  a 
most  intimate  mixture  of  charcoal,  sulphur  and  nitre  (potassic 
nitre),  the  last  named  substance  being  a  compound  containing 
a  very  large  percentage  of  oxygen,  which  can  be  liberated  on 
heating  it.  On  applying  a  light  to  gunpowder,"  we  raise  the 
temperature  sufficiently  to  allow  of  the  carbon  and  sulphur 
burning  in  the  oxygen  liberated  from  the  nitre;  and,  since  the 
three  substances  are  so  intimately  mixed  together,  this  com- 
bustion proceeds  with  explosive  rapidity,  and  produces  a  rela- 
tively enormous  quantity  of  hot  gas. 

Steel,  when  hardened,  decreases  in  specific  gravity,  con- 
tracts in  length  and  increases  in  diameter. 


140 
RULES  FOR  THE  FIREMAN. 

In  the  care  and  management  of  the  steam  boilef  the 
first  thing  required  is  an  unceasing  watchfulness  —  r,vatch- 
careis  the  very  word  which  describes  it.  The  accidents 
arising  from  neglect  or  incompetency  in  care  of  the  engine 
are  few  and  unimportant  compared  to  those  which  come 
from  negligence  in  attending  to  the  boiler. 

Hence  the  fireman  needs  to  be  a  man  possessed  of  some 
of  the  highest  qualities  of  manhood.  The  fact  that  many  of 
the  best  steam  engineers  in  the  country  have  begun  their 
careers  by  handling  the  shovel  is  evidence  that  good  men 
are  required  and  employed  in  this  capacity,  and  that  they 
are  rewarded  for  their  faithfulness  by  advancement. 

An  intemperate,  reckless  or  indifferent  man  should  never 
be  given  this  place  of  trust.  The  sooner  a  man  is  dismissed 
who  is  either  of  these  the  better,  both  for  himself  and  his 
employers,  to  say  nothing  of  the  innocent  and  unsuspecting 
public. 

!^A.n  employer  should  know  something  of  the  character 
and  habits  of  the  man  who  does  the  firing.  A  daily  visit, 
and,  at  irregular  times,  with  an  eye  to  things  in  the  boiler- 
room,  as  well  as  the  engine-room,  will  keep  him  posted,  to 
his  great  advantage.  This  regular  inspection  is  most  wel- 
come to  faithful  and  careful  men,  and  is  a  great  inspiration 
to  good  service.  A  steam -user  should  visit  his  steam  depart- 
ment as  regularly  as  he  does  his  office,  although  he  may  not 
spend  as  much  time  there.  The  failure  of  scores  of  other- 
wise flourishing  establishments  is  due  to  the  waste  and 
recklessness  in  the  use  of  fuel  under  the  boilers,  or  the 
heavy  losses  incurred  by  repairs  and  explosions  —  by  which 
the  whole  business  is  stopped  while  the  expenses  continue 
undiminished. 

A  feeling  of  conscientious  responsibility  should  be  the 
uppermost  thing  upon  the  mind  of  a  fireman  when  on  duty. 
He  should  consider  and  know  how  to  figure  the  total  tons  of 
pressure  upon  the  plates  of  his  boiler,  and  have  constantly  in 
mind  the  importance  of  unceasing  vigilance. 

To  know  how  to  be  a  good  fireman  cannot  be  taught  by 
a  book.  The  knowledge  comes  by  experience  and  by  instruc- 
tion of  engineers  who  have  themselves  been  good  firemen, 
but  the  following  are  some  of  the  hints  and  rules  which  may 
be  of  advantage  to  the  new  beginner.  #$ 

First —  The  fireman  should  be  a  sober  and  temperate 
person.  Frivolous  or  reckless  conduct  about  a  steam-boiler 
^entirely  out  of  place,  and  should  not  be  permitted.  There 


/s  too  much  danger  and  too  much  cost  —  not  to  call  it 
waste  —  of  fuel  to  allow  any  indifference  or  recklessness  in, 
the  man  upon  whom  so  many  depend. 

Second  —  The  fireman  should  be  punctual  in  beginning 
his  work.  A  loss  of  five  minutes  in  starting  into  vigorous 
activity  the  men  and  machines  of  an  establishment  is  some- 
times caused  by  inattention  of  the  fireman,  and  the  blame 
which  is  showered  upon  him  is  a  stern  reminder  that  he  is 
held  accountable  for  the  loss. 

Third  —  A  habit  of  neatness  is  an  almost  necessary  qual- 
ity, and  which  pays  better  for  the  cost  of  investment  than 
any  other. 

Fourth  —  The  tools  should  be  kept  hi  their  places,  and 
in  good  order. 

Fifth  —  The  boiler  and  all  its  attachments  should  be  kept 
in  the  very  tidiest  and  attractive  condition  possible. 

Sixth — The  fireman,  notwithstanding  its  apparent  diffi- 
culty, should  keep  himself  —  as  said  once  —  "respectable 
abjut  his  work."  Scattered  coal  and  ashes  and  dripping  oil 
should  be  constantly  cleaned  up,  and  every  effort  made  to 
make  the  boiler-room  an  attractive  and  cheerful  place. 

Seventh  —  The  fireman  needs  to  know  all  the  details  of 
his  work,  and  to  do  with  exactness  every  duty  imposed  upon 
him.  He  needs  to  be  cool  and  brave  in  the  presence  of 
unexpected  conditions,  such  as  sudden  leaks,  breakages  of 
the  glass  gauges  and  sudden  stoppages  of  the  engine  with  a 
heavy  head  of  steam  on.  ( 

Eighth  —  He  should  have  an  idea  of  the  importance  of  his 
work,  and  keep  in  mind  to  learn  to  do  everything  that  may 
fit  him  in  time  for  an  advanced  position. 

GRAPHITE  IN  STEAM-FITTING. 
Few  steam-fitters  or  engineers   understand   the  valuable 
properties  of  graphite   in   making  up  joints;  this  valuable 
mineral  cannot  be  overestimated  in  this  connection.     Inde- 
structib'e  under  all  changes  of  temperature,  a  perfect  lubn 
cant  and  an  anti-incrustator,  any  joint  can  be   mnde  up  per- 
fectly tight  with  it  and  can  be  taken  apart  years  a.ter  r.s  ensy 
as  put  together.      Rubber  or  metal  gaskets,  when  previous!} 
smeared  with  it,  will  last  almost  any  length  of  time,  and  wiH 
leave  the  surface  perfectly  clean  and  bright.     Few  engineer- 
put   t>   sea  without  a  good  supply  of  this  valuable  nuiier?! 
while  i     eems  to  be  airr.oot  overlooked  on  shore 


142 

HORSE  POWER  — NOMINAL,  INDICATED  AND 
EFFECTIVE,  WITH  RULES  FOR  DETERMIN- 
ING THE  HORSE  POWER  OF  AN  ENGINE. 

Engineers  and  others  who  never  carefully  considered 
the  matter,  often  use  the  three  terms  above  as  synonymous. 
While  the  terms  are  far  from  having  a  like  meaning,  still  we 
often  hear  the  nominal  horse  power  of  a  steam  engine  spoken 
of  when  the  person  using  the  expression  really  means  the 
indicated  power.  To  show  the  distinctive  difference  between 
the  meanings  of  the  words  nominal,  indicated  and  effective, 
as  applied  to  the  term  horse  power,  is  our  aim. 

A  horse  power  is  merely  an  expression  for  a  certain 
amount  of  work,  and  involves  three  elements  —  force,  space 
and  time.  If  the  force  be  expressed  in  pounds  and  the  space 
passed  through  in  feet,  then  we  have  a  solution  of,  and 
'meaning  for,  the  term  foot-pound ;  from  which  it  will  be 
seen  that  a  foot-pound  is  a  resistance  equal  to  one  pound 
moved  through  a  vertical  distance  of  one  foot.  The  work 
done  in  lifting  thirty  pounds  through  a  height  of  fifty  feet  is 
fifteen  hundred  foot-pounds.  Now,  if  the  foot-pounds 
required  to  produce  a  certain  amount  of  work  involve  a 
specified  amount  of  time  during  which  the  work  is  performed, 
and  if  this  number  of  foot-pounds  is  divided  by  the  equiva- 
lent number  representing  one  horse  power  (which  number 
will  depend  upon  the  time),  then  the  resulting  number  will 
be  the  horse  power  developed. 

^  For  example,  suppose  the  1,500  foot-pounds  just  spoken 
of  to  have  acted  in  one  second.  To  find  the  horse  power 
divide  by  550,  and  the  result  will  be  the  horse  power. 

A  horse  power  is  33,000  foot-pounds  per  minute;  or,  in 
other  words,  33,000  pounds  lifted  one  foot  in  one  minute,  or 
one  pound  lifted  33,000  feet  in  one  minute,  or  550  pounds 
lifted  one  foot  in  one  second,  etc. 

Ths  capacity  for  work  of  a  steam  engine  is  expressed  in 
the  number  of  horse  powers  it  is  capable  of  developing. 

Nominal  horse  power  is  an  expression  which  is  gradually 
going  out  of  use,  and  is  merely  a  conventional  mode  of 
describing  the  dimensions  of  a  steam  engine  for  the  con- 
venience of  makers  and  purchasers  of  engines.  The  mode 
of  computing  the  so-called  nominal  horse  power  was  estab- 
lished by  the  practice  of  some  of  the  early  English  manu- 
facturers, nnd  is  as  follows  : 

As  ume  the  velocity  of  the  piston  to  be  128  feet  per 
minute  m'Htipl-ird  by  the  cube  root  of  length  of  stroke  in  feet. 

Asftn  vi-  the  moral  effective  pressure  to  be  seven  pounds 


ner  square  inch.  From  these  fictitious  data  and  the  area  of 
the  piston  compute  the  horse  power  ;  that  is,  nomma.  hors* 
power- 7  X  128  X3  \f  stroke  in  feet  X  area  of  piston  m 
square  inches-f- 33, ooo.  , 

Indicated  horse  power  is  the  true  measure  of  the  work 
done  within  the  cylinder  of  a  steam  engine,  and  is  based  upon 
no  assumptions,  but  is  actually  calculated.  1  he  data  neces- 
sary are :  The  diameter  of  the  cylinder  in  inches,  length  in 
feet  the  me«n  effective  pressure  and  number  of  revolutions 
per  'minute.  As  we  have  before  stated,  or  implied,  work  is 
force  acting  through  space,  and  a  horse  power  is  the  amour 
of  work  in  a  specified  time.  In  a  steam  engine  the  force 
which  acts  is  the  product  of  the  area  of  the  piston  in  square 
inches  multiplied  by  the  mean  effective  pressure ;  the  space 
is  twice  the  stroke  in  feet,  or  one  complete  revolution,  mul- 
tiplied by  the  number  of  revolutions  per  minute. 

Therefore,  indicated  horse  power  equals  the  area  ot  tne 
piston,  multiplied  by  the  mean  effective  pressure,  multiplied 
by  the  piston  speed  in  feet  per  minute  divided  by  33,000 

Effective  horse  power  is  the  amount  of  work  which  an 
engine  is  capable  of  performing,  and  is  the  difference  be- 
tween the  indicated  horse  power  and  horse  power  required 
to  drive  the  engine  when  it  is  running  unloaded 

Engine  rating,  guarantees,  etc.,  are  usually  based  upon 
the  indicated  horse  power,  owing  to  the  c:se  and  accuracy 
with  which  it  can  be  determined,  and  as  a  means  ot  com- 
parison. 

Nominal  horse  power  is  computed  from  fictitious  data. 

Indicated  hoise  power  is  computed  from  actual  data, 
which  is  arrived  at  by  means  of  what  is  known  as  the  steam 
engine  indicator.  . 

Effective  horse  power  is  computed  from  actual  data, 
either  by  means  of  the  indicator,  brake  or  dynamometer. 

THE  CARE  OF  MACHINERY., 
The  monev  spent  in  keeping  machinery  clean  and  in 
order  is  by  no'  means  wasted.  The  better  the  machinery, 
the  greater  the  necessity  for  proper  supervision.  I  he  first 
knock  in  an  engine,  the  smallest  leak  in  a  boiler,  the  slight- 
est variation  from  truth  in  a  mill  spindle,  the  wearing  down 
of  roller  bearings,  heating  of  journals,  should  be  recti 
immediately.  The  smooth  and  even  working  of  machinery 
has  a  great  deal  to  do  with  the  cost  of  driving,  while  avoid- 
ance of  the  risk  of  breakage  saves  a  large  sum  that  would 
otherwise  be  spent  in  i  epairs. 


144 
FOAMING  IN   BOILERS. 

The  causes  are  dirty  water;  trying  to  evaporate  more 
water  than  the  size  and  construction  oi  the  boiler  is  intended 
for;  taking  the  steam  too  low  down;  insufficient  steam 
room;  imperfect  construction  of  boiler,  and  too  small  a 
steam  pipe. 

Take  a  kettle  of  dirty  water  and  place  it  on  a  fire  and 
allow  it  to  boil  and  watch  it  foam,  and  it  will  be  the  same  in 
a  boilei. 

Too  little  attention  is  paid  to  boilers  with  regard  to 
their  evaporating  power.  Where  the  boiler  is  large  enough 
for  the  water  to  circulate,  and  there  is  surface  enough  to 
give  oft  the  steam,  foaming  never  occurs.  As  the  particles 
of  steam  have  to  escape  to  the  surface  of  the  water  in  the 
boiler,  unless  that  is  in  proportion  to  the  amount  of  steam 
to  be  generated,  it  will  be  delivered  with  such  violence  that 
the  w4t£r  will  be  mixed  with  it  and  cause  what  is  called 
foaming. 

A  high  pressure  insures  tranquillity  at  the  surface,  and, 
the  steam  itself  being  more  dense,  it  comes  away  in  a  more 
compact  form,  and  the  ebullition  at  the  surface  is  no  greater 
than  at  a  lower  pressure.  When  a  boiler  foams,  we  close 
the  throttle  to  check  the  flow,  and  that  keeps  up  the  pres- 
sure and  lessens  the  sudden  delivery. 

>  Too  many  flues  in  a  boiler  obstruct  the  passage  of  the 
C'jeam  from  the  lower  part  of  the  boiler  on  its  way  to  the 
surface;  this  is  a  fault  in  construction,  but  nearly  all  foaming 
arises  from  dirty  water,  or  -from  trying  to  evaporate  too 
much  water  without  heating  surface  or  steam  room  enough. 
Usually,  when  first  put  in,  a  boiler  and  engine  are  large 
enough,  but,  as  business  increases,  more  machinery  is  added 
until  the  power  required  is  greater  than  can  be  furnished  by 
the  engine,  more  pressure  has  to  be  carried,  and  the  number 
of  revolutions  increased;  consequently  the  evaporating 
power  of  the  boiler  is  forced  beyond  its  ability,  the  steam 
being  drawn  off  so  rapidly  that  a  large  portion  of  water  is 
drawn  with  it  —  so  much  that  it  would  astonish  any  engineer 
if  he  had  a  testing  apparatus  attached  to  the  steam  pipe. 

For  the  remedy  of  foul  water  there  are  numerous  con- 
trivances to  prevent  it  from  entering  the  boiler,  which  is  a 
farbrtter  way  than  trying  to  extract  the  sediment  after  it  is 
there —  though  there  are  many  ingenious  methods  for  doing 
ihat  also..  Faulty  construction,  or  lack  of  capacity,  the 
engineer  cannot  help,  but  he  soon  learns  how  to  run  the 
boiler  to  get  the  best  possible  results  from  it. 


H5 

Every  intelligent  engineer  has  observed  that  his  engine 
has  an  individuality  not  possessed  by  any  other  he  ever  ran, 
and  nothing  but  personal  acquaintance  can  get  the  best  work 
out  of  it;  so  it  is  with  the  boiler. 

The  steam  pipe  may  be  carried  through  the  flange  six 
inches  into  the  dome,  which  would  prevent  the  water  from 
entering  the  pipes  by  following  the  sides  of  the  dome  as  it 
does. 

For  violent  ebullition  a  plate  hung  over  the  hole  where 
the  steam  enters  the  dome  from  the  boiler  is  a  good  thing, 
and  prevents  a  rush  of  water  by  breaking  it  when  the  throttle 
is  opened  suddenly. 

Clean  water,  plenty  of  surface,  plenty  of  steam  room, 
large  steam  pipes,  'boilers  large  enough  to  generate  steam 
without  forcing  the  fires,  are  all  that  is  required  to  prevent 
foaming.  A  surface  blow-off  is  a  grand  thing,  and  helps  a 
foaming  boiler,  and  would  be  a  good  thing  on  every  boiler, 
as  you  can  tlien  skim  it  as  you  would  an  open  kettle. 

HAND-HOLE  PLATES. 

They  should  be  placed  in  such  a  position  as  to  be  accessi- 
ble and  at  or  near  all  those  parts  of  the  boiler  where  scale  or 
sediment  is  liable  to  accumulate  In  the  locomotive  station- 
ary boiler  there  should  be  one  in  each  outside  corner  of  the 
fire  box  and  above  the  bottom  ring,  and  one  in  each  head 
under  the  tubes.  In  the  upright  tubular  there  should  be  at 
least  two  hand-hole  plates  above  the  ring,  and  one  over  the 
furnace  door,  on  a  line  with  the  lower  tube  sheet,  as  in  the 
locomotive  boner.  The  horizontal  boiler  should  have  one 
in  each  head  under  the  tubes,  and  the  rule  generally  observed 
is,  that,  whenever  sediment  is  deposited,  then  there  should  be 
a  hand-hole  to  get  at  it  for  a  regular  cleaning  out. 

These  plates  should  be  removed  once  a  month,  or  oftener 
if  necessary,  to  keep  them  clean,  and  are  never  considered 
an  article  of  ornament,  but  of  primary  importance. 

BOILING. 

Let  it  be  remembered,  that  the  boiling  spoken  of  so  often 
is  really  caused  by  the  formation  of  the  steam  particles,  and 
that,  without  the  boiling,  there  can  be  but  a  very  slight  quan- 
tity of  steam  produced. 

While  pure  water  boils  at  212°,  if  it  is  saturated  with 
common  salt,  it  boils  only  on  attaining  224°,  alum  boils  at 
220°,  sal  ammoniac  at  236°,  acetate  of  soda  at  256°,  pure 
nitric  acid  boils  at  248°,  and  pure  sulphuric  acid  at  620° 


I46 
INCRUSTATION  OF  STEAM  BOILERS. 

One  of  the  greatest  difficulties  to  be  contended  against  in 
steam  engineering  is  the  incrustation  on  the  boiler  walls,  aris- 
ing from  impure  water.  This  crust  is  a  poor  conductor  of  heat, 
and  causes  increased  fuel  consumption,  as  well  as  the  oxidiz- 
ing or  "  burning  "  of  the  plates,  owing  to  their  increased  tem- 
perature. A  plate  of  iron  37^  inches  thick  conducts  heat  as 
well  as  a  "  crust  "  of  one  inch.  A  boiler  bearing  scale  only 
1-16  inch  thick  requires  15  per  cent,  more  fuel,  with  %  inch 
60  per  cent,  more,  %  inch  150  percent,  more.  If  the  plates 
be  clean,  90  pounds  of  steam  require  a  plate  temperature  of 
only  325°  F. ;  that  is,  about  5°  above  the  steam  tempera- 
ture. But  if  there  be  a  y2  inch  scale,  or  crust,  the  plate 
must  be  heated  to  about  700°,  or  nearly  '•  low  red  "  heat. 
Now,  about  600°  iron  soon  gets  granular  and  brittle;  hence 
such  a  scale  is  dangerous  in  its  results.  Crust  also  retards 
the  circulation  of  the  water.  Two  very  common  ingredi- 
ents in  boiler  scale  are  carbonate  of  lime  and"sulphate  of 
lime,  or  gypsum.  The  moderate  use  of  soda  ash  (say  one 
part  in  5?°°°  °f  water)  holds  this  deposit  in  check,  by  pro- 
ducing from  the  principal  ingredients  a  neutral  carbonate  of 
lime,  which  will  not  adhere  to  the  plates,  when  thus  rapidly 
formed.  -Soda  ash,'  if  used  in  excess,  boils  up  and  passes 
into  the  cylinders  and  pumps,  clogging  up  valves  and  pistons 
by  combining  with  the  lubricants.  If  the  gauge-glasses 
become  muddy,  too  much  soda  water  is  used.  It  is  much 
better  to  supply  the  boilers  with  pure  water  that  can  deposit 
no  scale,  this  being  done  by  means  of  filters  and  heaters,  or 
by  surface-condensers,  and  being  especially  advisable  with 
sectional  and  water  tube  boilers. 

SUPERHEATED    STEAM. 

Superheated  steam  is  made  by  drawing  steam  from  the 
boiler  and  heating  it  after  it  has  ceased  to  be  in  contact  with 
the  water  in  the  boiler.  The  apparatus  by  which  the  extra 
heat  is  imparted  is  called  a  super-heater.  The  steam  is  con- 
ducted through  the  pipes,  and  hot  air  and  gases  of  combus- 
tion are  passed  around  the  outside  of  them,  thus  raising  the 
temperature  and  forming  a  more  perfect  gas. 

STEAM   GAUGES. 

Steam  gauges  indicate  the  pressure  of  steam  above  the 
atmosphere,  the  total  pressure  being  measured  from  a  per- 
fect vacuum,  which  will  add  14  7-10  pounds  on  the  average 
to  the  pressure  shown  on  the  steam  gauge. 


H7 

IMPORTANT    TO    THOSE    OPERATING    STEAM 
BOILERS. 

In  view  of  the  numerous  boiler  explosions  that  have 
recently  occurred,  we  submit  to  them  the  following  perti- 
nent questions  asked  by  the  American  Machinist,  which 
should  command  the  careful  consideration  of  every  steam 
user  in  the  land: 

How  long  since  you  were  inside  your  boiler? 

Were  any  of  the  braces  slack? 

Were  J«ny  of  the  pins  out  of  the  braces? 

Did  all  the  braces  ring  alike? 

Did  not  some  of  them  sound  like  a  fiddle-string? 

Did  you  notice  any  scale  on  flues  or  crown  sheet? 

If  you  did,  when  do  you  intend  to  remove  it? 

Have  you  noticed  any  evidence  of  bulging  in  the  fire-box 
plates? 

Do  you  know  of  any  leaky  socket  bolts? 

Are  any  of  the  flange  joints  leaking? 

Will  your  safety  valve  blow  off  itself,  or  does  it  stick  a 
little  sometimes? 

Are  there  any  globe  valves  between  the  safety  valve  and 
the  boiler?  They  should  be  taken  out  at  once,  if  there  are. 

Are  there  any  defective  plates  anywhere  about  your 
boiler  ? 

Is  the  boiler  so  set  that  you  can  inspect  every  part  of  it 
when  necessary? 

If  not,  how  can  you  tell  in  what  condition  the  plates  are? 

Are  not  some  of  the  lower  courses  of  tubes  or  flues  in 
your  boiler  choked  with  soot  or  ashes? 

Do  you  absolutely  know,  of  your  own  knowledge,  that 
your  boiler  is  in  safe  and  economical  working  order,  or  do 
you  merely  suppose  it  is? 

HOW  TO    PREVENT   ACCIDENTS   TO    BOILERS. 

I st.     Carry  regular  steam  pressure. 

2d.  Start  the  engine  slowly  so  as  not  to  make  a  violent 
change  in  the  condition  of  the  water  and  steam,  aiw*.  when 
consistent,  stop  the  engine  gradually. 

3d.     Carry  sufficient  water  in  the  boiler. 

4th.  Do  not  exceed  the  pressure  in  pounds  per  square 
inch  allowed  to  be  carried. 

5th.  See  that  every  appliance  of  the  boiler,  feed  pipes 
and  safety-valve,  fusible  plugs,  etc.,  are  in  complete  working 
order. 


I48 

PRINCIPLES  ON  WHICH    BOILERS  AND  THEIR 
FURNACES  SHOULD  BE  CONSTRUCTED. 

Hitherto,  those  who  have  made  boiler-making  a  sepa- 
rate branch  of  manufacture,  have  given  too  much  attention 
to  mere  relative  proportions.  One  class  place  reliance  on 
enlarged  grate  surface,  another  on  large  absorbing  surfaces, 
while  a  third  demand,  as  the  grand  panacea,  "boiler-room 
enough,"  without,  however,  explaining  what  that  means. 
Among  modern  treatises  on  boilers,  this  principle  of  room 
enough  seems  to  have  absorbed  all  other  considerations,  and 
the  requisites,  in  general  term*,  are  thus  summed  up  : 

1.  Sufficient  amount  of  internal  heating  surface. 

2.  Sufficient  roomy  surface. 

3.  Sufficient  air-space  between  the  bars. 

4.  Sufficient  area  in  the  tubes  or  flues  ;  and 

5.  Sufficiently  large  fire-bar  surface. 

In  simpler  terms,  these  amount  to  the  truism  —  give  suf- 
ficient size  to  all  the  parts,  and  thus  avoid  being  deficient 
in  any. 

With  reference  to  the  proportions  of  the  several  parts  of 
a  furnace,  there  are  two  points  requiring  attention ;  fust, 
the  superficial  area  of  the  grate  for  retaining  the  solid  fuel 
or  coke  ;  and,  second,  the  sectional  area  of  the  chamber 
above  the  fuel  for  receiving  the  gaseous  portion  of  the  coal. 

As  to  the  area  of  the  grate-bars,  seeing  that  it  is  a 
solid  body  that  is  to  be  laid  on  them,  requiring  no  more 
space  than  it  actually  covers  at  a  given  depth,  it  is  alone 
important  that  it  be  not  too  large.  On  the  other  hand,  as 
to  the  area  of  the  chamber  above  the  coal,  seeing  that  it  is 
to  be  occupied  by  a  gaseous  body,  requiring  room  for  its 
rapidly  enlarging  volume,  it  is  important  that  it  be  not  too 
small. 

As  to  the  best  proportion  of  the  grate,  this  will  be  the 
easiest  of  adjustment,  as  a  little  observation  will  soon  enable 
the  engineer  to  determine  the  extent  to  which  he  may 
increase  or  diminish  the  length  of  the  furnace.  In  this 
respect  the  great  desideratum  consists  in  confining  that 
length  within  such  limits  that  it  shall,  at  all  times, 
be  well  and  uniformly  covered.  This  is  the  absolute 
condition  and  sine  qua  non  of  economy  and  efficiency; 
yet  it  is  the  very  condition  which,  in  practice,  is  the 
i  lost  neglected.  Indeed,  the  failure  and  uncertainty  which 
has  attended  many  anxiously  conducted  experiments  has  most 
frequently  arisen  from  the  neglect  of  this  one  condition. 

If   ihe  grate-bars  be  not  equally  and  well  covered,   the 


149 

fr  will  enter  in  irregular  and  rapid  streams  or  masses, 
j^rough  the  uncovered  parts,  and  at  the  very  time  when  it 
should  be  there  most  restricted.  Such  a  state  of  things  at 
once  bids  defiance  to  all  regulation  or  control.  Now,  on  the 
control  of  the  supply  of  air  depends  all  that  human  skill  can 
do  in  effecting  perfect  combustion  and  economy  ;  and,  until 
the  supply  of  fuel  and  the  quantity  on  the  bars  be  regulated, 
it  will  be  impossible  to  control  the  admission  of  the  air. 

Having  spoken  of  the  grate-bar  surface,  and  what  is 
placed  on  it,  we  have  next  to  consider  the  chamber 
part  of  the  furnace,  and  what  is  formed  therein.  In  marine 
and  cylindrical  land  boilers,  this  chamber  is  invariably  made 
too  shallow  and  too  restricted. 

The  proportions  allowed  are  indeed  so  limited  as  to  give 
it  rather  the  character  of  a  large  tube,  whose  only  function 
should  be,  the  allowing  the  combustible  gases  to  pass  through 
it,  rather  than  that  of  a  chamber,  in  which  a  series  of  consecu- 
tive chemical  processes  were  to  be  conducted.  Such 
furnaces  by  their  diminished  areas,  have  also  this  injurious 
tendency, --that  they  increase  the  already  too  great  rapidity 
of  the  current  through  them.  ^ 

The  constructing  the  furnace  chamber  so  shallow  an\ 
with  such  inadequate  capacity,  appears  to  have  arisen  from 
the  idea,  that  the  nearer  the  body  to  be  heated  was  brought 
to  the  source  of  heat,  the  greater  would  be  the  quantity 
received.  This  is  no  doubt  true  when  we  present  a  body  to 
be  heated  in  front  of  a  fire.  When,  however,  the  approach 
of  the  colder  body  will  have  the  direct  effect  of  interfering 
with  the  processes  of  nature  (as  in  gaseous  combustion),  it 
must  manifestly  be  injurious.  Absolute  contact  with  flame 
should  be  avoided  where  the  object  is  to  obtain  all  the  heat 
which  would  be  produced  by  the  combustion  of  the  entire 
constituents  of  the  fuel. 

So  much,  however,  has  the  supposed  value  of  near  ap- 
proach, and  even  impact,  prevailed,  that  we  find  the  space 
behind  the  bridge,  frequently  made  but  a  few  inches  deep, 
and  bearing  the  orthodox  title  of  the  flame-bed.  Sounder 
views  have,  however,  shown  that  it  should  be  made  capa- 
cious, and  the  impact  of  the  flame  avoided. 

As  a  general  view,  deduced  from  practice,  it  may  De 
stated  that  the  depth  between  the  top  of  the  bars  and  the 
crown  of  the  furnace  should  not  be  less  than  two  feet  six 
inches  where  the  grate  is  but  four  feet  long  ;  increasing  in 
the  same  ratio  where  the  length  is  greater  ;  and  secondly, 
that  the  depth  below  the  bars  should  not  be  less,  although 
depth  there  is  not  so  essential  either  practically  or  chemically. 


150 
PROPERTIES  OF  SATURATED  STEAM. 


PRESSURE. 

VOLUME. 

Total  heat 

required 

Tempera- 

Latent 

to  generate 

By 

Steam 
Gauge. 

Total 

ture  in 
Fahrenheit 
Degrees 

Com- 
pared 
.     with 
Water. 

Cubic  Feet 
of  Steam 
from  i  Ib. 
of  Water. 

Heat  in 
Fahren- 
heit 
Degrees. 

I   Ib.     Of 

Steam  from 
Water  at  32 
deig.    under 
constant 

pressure. 

In  Heat 

Units. 

o 

15 

212.  0 

1642 

26.36 

965.2 

146.1 

5 

20 

228.0 

1229 

19.72 

952-8 

150.9 

.0 

25 

240.1 

996 

15-99 

945-3 

154.6 

IS 

3° 

250.4 

838 

13-46 

937-9 

157-8 

20 

35 

259-3 

726 

11.65 

931.6 

160.5 

25 

40 

267.3 

640 

10.27 

926.0 

162.9 

3° 

45 

274.4 

572 

9.18 

920/9 

165.1 

35 

5° 

281.0 

5i8 

8.31 

916.3 

167.  r 

40 

55 

287.  i 

474 

7.61 

912.0 

169.0 

45 

60 

292.7 

437 

7.01 

908.0 

170.7 

50 

65 

298.0 

405 

6.49 

904.2 

172.3 

55 

70 

302.9 

378 

6.07 

900.8 

173-3 

60 

75 

307-5 

353 

5-68 

897.5 

175-2 

65 

80 

312.0 

333 

5  35 

894.3 

176.5 

70 

85 

316.1 

3U 

5-05 

891.4 

177.9 

75 

90 

320.2 

298 

4-79 

888.  s 

179-1 

80 

95 

324-1 

283 

4-55 

8858 

180.3 

85 

100 

327-9 

270 

4-33 

883.1 

181.4 

9° 

105 

33i-3 

257 

4.14 

880.7 

182.4 

95 

I  TO 

334-6 

247 

3-97 

878.3 

183-5 

100 

H5 

338.o 

237 

3.80 

875-9 

184.5 

no 

125 

344-2 

219 

3-5i 

871-5 

186.4 

I2O 

135 

350.1 

203 

3-27 

867.4 

188.2 

130 

145 

355-6 

190 

3.06 

863-5 

189.9 

140 

155 

361.0 

179 

2.87 

859-7 

I9I-5 

150 

I65 

366.0 

169 

2.71 

856.2 

192.9 

1  60 

175 

370.8 

159 

2.56 

852.9 

194.4 

170 

l85 

375-3 

151 

2-43 

849.6 

195-8 

1  80 

195 

379-7 

144 

2.31 

846.5 

197.2 

This  table  gives  the  value  of  all  properties  of  saturated 
steam  required  in  calculations  connected  with  steam  boilers. 

SODA  ASH  IN  BOILERS. 

An  English  boiler  inspection  company  recommends  that 
soda  ash  be  used  to  prevent  scale,  instead  of  soda  crystals; 
and  that  it  be  pumped  in  regularly  and  continuously  in  solu- 
tion, with  the  feed,  instead  of  spasmodically  dumped  in  solid 
through  the  manhole.  Tungstate  of  soda,  instead  of  either 
soda  ash  or  soda  crystal,  has  been  recommended  strongly  by 
some  high  authorities  in  lieu  of  the  above. 


STEAM  COAL. 

Steam  coal,  being,  as  everybody  knows,  unquestionably 
the  most  important  and  largest  expense  in  the  manufacture 
of  steam,  is  deserving  a  most  careful  investigation  by  engi- 
neers and  owners,  who,  unlike  chemists  and  college  pro- 
fessors, consider  the  subject  wholly  in  a  practical  way,  as 
relating  to  the  coal  bills  of  their  establishments. 

Useful  knowledge  of  e very-day  economy  of  coal  is  seldom 
gained  by  "  tests"  conducted  by  experts,  for  several  reasons  so 
plain  that  they  will  not  require  explanation.    1st.  The  cost  of 
the  fuel  used  in  tests,  whatever  may  be  stated,  is  too  high,  aver- 
age or  "  every-day  "  coal  not  being  used.     The  experiments 
are  made  with  picked  men  and  picked  fuel,  for  brief  period* 
with  everything  at  its  best,  and  the  results  attained,  iflookt^ 
for  in  the  ordinary  run  of  business,  will  be  disappointmerj 
in  the  results  of  the  wholesale  order.     2d.     Men,  working  rf 
firemen,  twelve  or  fourteen  hours  per  day  in  the  hot  furnac  « 
rooms,  cannot  be  expected,  with  the  ordinary  appliances,  t  4 
watch  where  every  lump  of  coal  falls  when  feeding  the  fur 
nace*,  nor  to  clean  the  grates  any  oftener  than  they  are  cor* 
pelled  to  do.     3d.   Moreover,  too  many  employers  favor  t\ 
low  wages  plan,  and,  for  the  apparent  saving  of  a   few  do" 
lars  per  month,  waste  many  times  the  amount   in  the;r  fu 
nace  doors,  and  render  their  establishments  most   disagrt" 
able  to  their  neighbors,  by  a  free  distribution  of  unconsmn-^* 
carbon,  or  what  is  commonly  called  soot,  and  of  which  most 
people  have  no  appreciation.     4.   Little  or  no  encourage- 
ment is   given  for  careful  or  economical  firing,  as  a  rule. 
The  fireman  who  oftentimes  wastes  as  much  as  his  entire 
wages,  secures  the  same  pay  as  the  man  working  alongside 
of  him  who  saves  it  all.     It  maybe  remarked  that  this  is 
"  not  business,"  but  many  are  the  concerns  who  run  their 
steam  plants  upon  this  system.     Careful  handling  of  coal  in 
firing  pays  better  than  any  other  thing  about  a  steam  plant, 
and  it  is  the  wisest  economy  to  secure  good  and  careful  men 
to  do  it. 

As  is  well  understood,  the  conditions  or  circumstances 
attending  the  combustion  of  coal  for  steam  purposes,  embra- 
ces a  wide  range.  A  very  few  establishments  work  under 
conditions  that  admit  of  a  high  attainment  of  economy  by 
having  a  fixed  performance  of  duty,  and  their  plants  well 
proportioned  to  the  regular  work,  but  by  far  the  largest 
number  having  a  fluctuating  demand  for  steam,  and  in  that 
respect  are  largely  at  a  disadvantage.  Many  furnaces  are 
badly  constructed.,  others  suffer  from  an  insufficiency  of 


152 

draft,  and  in  many  cases  there  seems  to  be  no  end  of  compli- 
cations detrimental  to  best  results. 

These  practical  difficulties  and  uncertainties,  which  are  well 
known  to  every  experienced  engineer,  render  any  investiga- 
tion worthy  of  the  name,  slow  and  laborious.  It  has  taken 
considerable  time  and  research  to  arrive  at  the  conclusion, 
though  differing  from  the  preponderance  of  hearsay 
or  guess-work  evidence,  that  now,  at  least,  "  the  highest 
priced  coal  is  not  the  cheapest  for  steam  production^ 
and  that,  in  fact,  the  reverse  is  undoubtedly  true,  especially 
in  the  Western  country  Late  improvements  in  the  con- 
struction of  grate  bars  ha^e  undoubtedly  added  largely  to 
the  value  of  Western  soft  coals.  The  great  difficulty,  in 
former  times,  of  ridding  the  furnaces  of  the  incombustible 
part  of  these  very  valuable  coals,  has  now  been  removed  by 
improvements,  and  there  is  no  doubt  but  what  a  large  num- 
ber of  extensive  establishments  in  the  West  are  now,  and  for 
some  time  past  have  been,  obtaining  the  same  duty  from  the 
Illinois  bituminous  coals  that  they  in  former  years  obtained 
from  the  high-priced  Eastern  coals. 

BLOWING  OFF  UNDER  PRESSURE. 

A  boiler  can  be  seriously  impaired  by  blowing  it  down 
under  a  high  pressure,  and  with  hot  brick  work.  The  heat 
from  the  latter  will  granulate  the  iron  and  reduce  its  tensile 
strength.  A  boiler  should  not  be  blown  right  down  under 
a  higher  pressure  than  twenty  pounds,  and  not  less  than  four 
hours  after  the  fire  has  been  drawn. 

When  a  boiler  is  exposed  to  cold  air,  especially  in  the 
winter,  it  is  advisable  that  the  damper  be  closed  and  the 
doors  thrown  open,  or  vice-versa.  If  both  are  left  open, 
the  strong  draught  of  cold  air  will  cool  off  the  flues  faster 
than  the  shell;  which  abuse,  if  kept  up,  would  reduce  the 
length  of  the  life  of  the  boiler. 

THE  TOTAL  PRESSURE. 

A  boiler  eighteen  feet  in  length  by  five  feet  in  diameter, 
with  forty-four  inch  tubes,  under  a  head  of  eighty  pounds  of 
steam,  has  a  pressure  of  nearly  113  tons  on  ea^h  head,  1,625 
tons  on  the  shell  and  4,333  tons  on  the  tubes,,  making  a  total 
of  6,184  tons  on  the  whole  of  the  exposed  surfaces. 

This  calculation  is  made  by  finding  the  total  square  inches 
under  pressure,  and  multiplying  the  totals  by  the  pressure,  in 
this  case,  80  pounds  to  the  square  inch. 


Table  Showing  Safe    Working  Steam  Pressure  for   Iron 
Boilers  of  different  sizes,  using  a  Factor  of  Safety  of  Six. 


ill! 

J2 

.-  "" 

Longitudinal  Seams, 
Single  Riveted. 

Longitudinal  Seams, 
Double  Riveted. 

11  .a 

H^ 

Tensil  Strength  of  Iron. 

Tensil  Strength  of  Iron. 

45,000 

50.000 

55,°oo 

45,000 

50,000 

55,000 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

Press- 

Press- 

Press- 

Press- 

Press- 

Press- 

ure. 

ure. 

ure 

ure. 

ure. 

ure. 

• 

36 

i 

104 
I30 

116 
145 

127 
159 

156 

139 
174 

152 

38 

7 

99 
123 

1  10 

137 

121 

119 

148 

132 
l64 

\  8  1 

40 

1 

1.17 

104 
130 

H3 

113 
140 

125 

I56 

138 
172 

42 

X 

89 

112 

99 
124 

109 
136 

107 
134 

149 

163 

44 

1 

85 
107 

95 
118 

104 
130 

102 

128 

114 
142 

156 

46 

i 

82 
102 

"3 

100 
125 

98 
122 

109 
136 

120 
150 

X 

78 

87 

96 

94 

104 

115 

48 

& 

98 

109 

120 

118        131 

144 

y% 

118 

131 

144 

142        157 

173 

yt 

75 

83 

92 

90      ;            IOO 

IIO 

5O 

94 

104 

115 

113                  125 

138 

y& 

112 

125 

138 

134  !    150 

1  66 

( 

x 

72 

80 

88 

86  i       96 

106 

52   ] 

90 

100 

IIO 

108       120 

132 

} 

y% 

108 

120 

132 

130      144 

158 

£ 

87 

96  i 

106 

101           112 

122 

54  j 

y& 

104 

116 

127 

120          134 

148 

( 

\ 

121 

78 

135 

87 

148 
95 

140          156 

94        104 

172 
114 

60   \ 

H 

94 

104 

113        125 

138 

I 

il> 

109 

121 

134 

I31   i     H5 

160 

85 

95 

104 

102           114 

125 

66 

ft 

99 

in 

121 

120 

133 

146 

1 

/^ 

112 

117 

138 

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152 

167 

3/£ 

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9I           102 

112 

IIO           122 

134 

102    I       117 

128 

125  !   140 

153 

154 
STEAM    HEATING. 

The  advantages  of  steam  heating  are  set  forth  by  Prof. 
W.  P.  Trowbridge,  in  the  North  American  Review,  as 
follows  : 

1.  The  almost  absolute  freedom  from  risk  of  fire  when 
the  boiler  is  outside  of  the  walls  of  the  building  to  be  heated, 
and  the  comparative  immunity  under  all  circumstances. 

2.  When  the  mode  of  heating  is  the  indirect  system, 
with  box  coils  and  heaters  in  the  basement,  a  most  thorough 
ventilation  may  be  secured,  and  it  is  in  fact  concomitant  with 
the  heating. 

3.  Whatever  may  be  the  distance  of  the  rooms  from  the 
source  of  heat,  a  simple  steam  pipe  of  small  diameter  con- 
veys the  heat.     From  the  indirect  heaters  underneath  the 
apartments  to  be  heated,  a  vertical  flue  to  each'  apartment 
places  the  flow  of  the  low  heated  currents  of  the  air  under 
the   absolute  control   of  the  occupants  of   the  apartment. 
Uniformity  of  temperature,  with  certainty  of  control,  may 
be  thus  secured. 

4.  Proper  hygrometric  conditions  of  the  air  arc  better 
attained.      As   the  system    supplies  large  volumes   of    air 
heated  only  slightly  above  the  external  temperature,  there  is 
but  little  change  in  the  relative  degree  of  moisture  of  the  air 
as  it  passes  through  the  apparatus. 

5.  No  injurious  gases  can  pass  from  the  furnace  into  the 
air  flues. 

6.  When  the  method  of  heat  is  by  direct  radiation  in 
the  rooms,  the  advantage  of  steadiness  and  control  of  tem- 
perature, sufficient  moisture  and  good  ventilation,  are  not 
always  secured;  but  this  is  rather  the  fault  of  design,  since 
all  these  requirements  are  quite  within  reach  of  ordinary 
contrivances. 

7.  One  of  the  conspicuous  advantages  of  steam  heating 
is  that  the  most  extensive  buildings,  whole  blocks,  and  even 
large  districts  of  a  city  may  be  heated  from  one  source,  the 
steam  at  the  same  time  furnishing  power  where  needed  for 
ventilation  or  other  purposes,  and  being  immediately  avail- 
able also  for  extinguishing  fires,  either  directly  or  through 
force  pumps. 

STOPPING  WITH  A  HEAVY  FIRE. 

When  it  becomes  necessary  to  stop  an  engine  with  a  heavy 
fire  in  the  furnace,  place  a  layer  of  fresh  coal  on  the  fire,  shut 
the  damper  and  start  the  injector  or  pump  for  the  purpose  of 
keeping  up  the  circulation  in  the  boiler. 


ANALYSIS  OF  BOILER  INCRUSTATION. 

BY  DR.  WALLACE. 

Carbonate  of  lime 64.98 

Sulphate  of  lime 9. 33 

Magnesia 6.93 

Combined  water 3. 15 

Chloride  of  sodium 23 

Oxide  of  iron. 1. 36 

Phosphate  of  lime  of  alumina 3.72 

Silica 6.60 

Organic  matter 1.60 

Moisture  at  212  degrees  F 2. 10 

100. 
CLEANING  BOILER  TUBES. 

The  method  of  cleaning  boiler  tubes  depends  upon  the 
kind  of  fuel  used.  A  steam  jet  will  not  answer  where  wood 
and  soft  coal  are  used,  but  will  do  for  hard  coal,  though  in 
any  case  a  scraper  is  indispensable,  where  a  steam  jet  is  not. 
Soot  and  dust  will  collect  in  the  tubes  and  burn  on  so  as  to 
require  more  than  a  jet  of  steam  to  move  it.  A  steam  jet  or 
blower  should  be  used  only  where  dry  steam  is  at  hand,  but 
by  no  means  with  wet  steam.  Before  using  the  jet,  thor- 
oughly blow  all  the  water  out  of  it  and  heat  it  up.  We  have 
seen  some  men  put  the  point  of  the  jet  in  a  tube  and  turn  on 
steam  before  warming,  and  then  wonder  what  caused  the  brick 
work  to  crumble  away  at  the  back  end . 

CLEANING  BRASS. 

The  government  method  prescribed  for  cleaning  brass, 
and  in  use  at  all  the  United  States  arsenals,  is  said  to  be 
the  best  in  the  world.  The  plan  is,  to  make  a  mixture  of 
one  part  of  common  nitric,  and  one-half  part  sulphuric  acid 
in  a  stone  jar,  having  also  a  pail  of  fresh  water  and  a  box  of 
saw-dust.  The  articles  to  be  treated  are  first  dipped  into 
the  acid,  then  removed  into  the  water,  and  finally  rubbed 
with  the  saw- dust.  This  immediately  changes  them  into  a 
brilliant  color.  If  the  brass  has  become  greasy,  it  is  first 
dipped  into  a  strong  solution  of  potash  or  soda,  in  warm 
water.  This  dissolves  the  grease,  so  that  the  acid  has  power 
to  act. 

THE  THERMAL  UNIT 

Is  the  heat  necessary  to  raise  one  pound  of  water  at  39°  F. 
one  degree,  or  to  40°  F. 


SMOKE  — HOW  FORMED. 

When  fresh  coal  is  placed  on  a  fire  in  an  open  grate, 
smoke  arises  immediately;  and  the  cause  of  this  smoke  is  not 
far  to  seek,  as  it  will  be  easily  understood  that,  before  fresh 
coals  were  put  upon  the  fire  within  the  grate,  the  glowing 
coals  radiated  their  heat  and  warmed  the  air  above,  and 
thereby  enabled  the  rising  gases  to  at  once  combine  with  the 
warmed  air  to  produce  combustion;  but,  when  the  fresh  coals 
are  placed  upon  the  fire,  they  absorb  the  heat,  and  the  air 
above  remains  cold. 

By  gases,  is  meant  the  gases  arising  from  coals  while  on 
or  near  the  fire,  and  it  may  not  be  known  to  every  one  that 
we  do  not  burn  coals,  oils,  tallow  or  wood,  but  only  the 
gases  arising  from  them.  This  can  be  made  clear  by  the 
lighting  of  a  candle,  which  will  afford  the  information 
required.  By  lighting  the  candle,  fire  is  set  to  the  wick, 
which,  by  its  warmth,  melts  a  small  quantity  of  tallow 
directly  absorbed  by  the  capillary  tubes  of  the  wick,  and 
thereby  so  very  finely  and  thinly  distributed  that  the  burning 
wick  has  heat  enough  to  be  absorbed  by  the  small  quantity 
of  dissolved  tallow  to  form  the  same  into  gases,  and  these 
gases  burning,  combined  with  the  oxygen  in  the  atmosphere, 
give  the  light  of  the  candle.  A  similar  process  is  going  on 
in  all  other  materials;  but  coal  contains  already  about  sev- 
enteen per  cent,  of  gases,  which  liberate  themselves  as  soon 
as  they  get  a  little  warm.  The  smaller  the  coal,  the  more 
rapidly  will  the  gases  be  liberated,  so  that,  in  many  cases, 
only  part  of  the  gases  are  consumed. 

The  fact  is,  that  the  volatile  gases  from  the  coal  cannot 
combine  with  cold  air  for  combustion.  Still  combustion 
takes  place  in  the  following  ways.  The  cold  air,  in  the  act 
of  combination,  absorbs  a  part  of  the  warmth  of  the  rising 
gases,  which  they  cannot  spare,  and,  therefore,  must  con- 
dense, so  that  small  particles  are  formed,  which  aggregate 
and  are  called  smoke,  and  when  collected,  produce  soot;  but 
as  long  as  these  particles  and  gases  are  floating,  they  cannot 
burn  or  produce  combustion,  as  they  are  surrounded  by  a 
thin  film  of  carbolic  acid.  It  is  only  when  collected  and  this 
acid  driven  off,  that  they  are  consumed. 

It  has  now  been  shown  that  cold  is  the  cause  of  smoke, 
which  may  be  greatly  reduced  by  care.  In  the  open  fire 
grate  the  existing  fire  ought  to  be  drawn  to  the  front  of  the 
grate,  and  the  fresh  coal  placed  behind,  or  in  the  back  of  the 
fire  The  fire  in  the  front  will  then  burn  more  rapidly, 
warm  the  air  above,  and  prepare  the  raising  gases  for  com- 


157 

bustion.      in   this   way  smoke   is   diminished,  as  the 
from  the  coals  at  the  back  rise  much  more  slowly  then  when 
placed  upon  the  fire  and  the  air  partly  warmed. 


WHAT  IS  LATENT  HEAT? 

Heat  has  its  equivalent  in  mechanical  work,  and,  when 
heat  disappears,  work  of  some  kind  will  take  its  place. 
When  a  body  changes  from  the  liquid  to  the  gaseous  form, 
the  molecules  have  to  be  separated  and  placed  in  different 
positions  with  regard  to  each  other.  This  calls  for  an  ex- 
penditure of  work.  This  work  is  supplied  by  heat,  which 
disappears  at  the  time.  One  can  hold  his  hand  in  steam  es- 
caping from  a  safety  valve  of  a  boiler  for  this  reason.  The 
heat  of  the  steam  disappears  in  pushing  apart  and  rearrang- 
ing the  molecules  of  the  steam  as  it  expands  when  it  leaves 
the  safety  valve. 

The  term  latent  heat,  as  commonly  used,  means  the 
amount  of  heat  which  disappears  when  water  changes  from  a 
liquid  into  steam.  This  is  considerable,  as  will  be  seen  by 
consulting  any  table  of  the  heat  contained  in  steam,  and  the 
water  from  which  it  comes. 

Water  at  212°  contains  180  units  of  heat.  Steam  at 
212°  contains  1,146  units  of  heat.  The  latent  heat  is  the 
difference  of  966  links.  Such  a  large  quantity  disappears 
when  liquid  water  changes  to  steam,  that  boiling  cannot  be 
raised  above  212°,  no  matter  how  hard  it  is  boiled.  The 
heat  becomes  latent,  and  the  mechanical  work,  or  rather 
molecular  work,  is  sufficient  to  take  up  all  that  is  supplied  by 
the  fire. 

The  specific  heat  of  air  at  constant  pressure  being 
0.2377,  the  specific  heat  of  water,  which  is  i,  is,  therefore, 
4.1733  times  greater  under  ordinary  circumstances.  A 
pound  oi  water  losing  i°  of  heat,  or  one  thermal  unit,  will 
consequently  raise  the  temperature  of  4.17  pounds,  or,  at 
ordinary  temperatures,  say  50'  of  air,  i°.  A  pound  of  steam 
at  atmospheric  pressure,  having  a  temperature  of  212°  F., 
in  condensing  to  water  at  212°  F.,  yields  966  thermal  units, 
which,  if  utilized,  would  raise  the  temperature  of  5X966= 
4830'  of  air  i°,  or  about  690'  from  5°  to  70°  F. 


i58 
MISTAKES  IN  DESIGNING   BOILERS. 

One  of  the  greatest  mistakes  that  can  be  made  in  design- 
ing boilers,  and  the  one  that  is  most  frequently  made  of  any, 
consists  in  putting  in  a  grate  too  large  for  the  heating  sur- 
face of  the  boiler,  so  that  with  a  proper  rate  of  combustion 
of  the  fuel  an  undue  proportion  of  the  heat  developed  passes 
off  through  the  chimney,  the  heating  surface  of  the  boiler 
being  insufficient  to  permit  its  transmission  to  the  water. 
This  mistake  has  been  so  long  and  so  universally  made,  and 
boiler  owners  have  so  often  had  to  run  slow  fires  under  their 
boilers  to  save  themselves  from  bankruptcy,  that  it  has  given 
rise  to  the  saying,  "  Slow  combustion  is  necessary  for  econ- 
omy." This  saying  is  considered  an  axiom,  and  regarded 
with  great  veneration  by  many,  when  the  fact  is,  if  the 
truth  must  be  told,  it  has  been  brought  about  by  the  waste- 
fulness entailed  by  boiler  plants  and  proportioned  badly  by 
ignorant,  boilermakers  and  ignorant  engineers,  who  ought  to 
know  better,  but  don't. 

Let  us  consider  the  matter  briefly  :  Suppose  we  are 
running  the  boiler  at  a  pressure  of  80  tbs.  per  square  inch, 
the  temperature  of  the  steam  and  water  inside  will  be  about 
325  degrees  F. ;  the  temperature  of  the  fire  in  the  furnace 
will,  under  ordinary  conditions,  be  about  2,500  degrees  F. 
Now,  it  should  be  clear  to  the  dullest  comprehension,  that 
we  can  transmit  to  the  water  in  the  boiler  only  that  heat  due 
to  the  difference  between  the  temperature  in  the  furnace  and 
that  in  the  boiler.  In  case  of  the  above  figures,  about 
seven-eighths  of  the  total  heat  of  combustion  is  all  that 
could,  by  any  possibility,  be  utilized,  and  this  would  require 
that  radiation  of  heat  from  every  source  should  be  absolutely 
prevented,  and  that  the  gases  should  leave  the  boiler  at  the 
exact  temperature  of  the  steam  inside,  or  325  degrees. 

To  express  the  matter  plainly,  we  may  say  that  the 
utilization  of  the  effect  of  a  fall  of  temperature  of  2.175 
degrees  is  all  that  is  possible. 

Now,  suppose,  as  one  will  actually  find  to  be  the  case  in 
many  cases  if  he  investigates  carefully,  that  the  gases  leave 
the  flues  of  another  steam  boiler  at  a  temperature  between 
500  and  600  degrees.  The  latter  temperature  will  be  found 
quite  common,  as  it  is  considered  to  give  "good  draft." 
This  is  quite  true,  especially  as  far  as  the  "  draft "  on  the 
owner's  pocket-book  is  concerned,  for  he  cannot  possibly 
utilize  under  these  conditions  more  than  2,500 — 500=2,000 
degrees  of  that  inevitable  difference  of  temperature  to  which 
he  is  confined,  or  four-fifths  of  the  total,  instead  of  the 


seven-eighths,  as  shown  above,  where  the  boiler  was  running 
just  right,  and  any  attempt  to  reduce  the  temperature  of  the 
escaping  gases  by  means  of  slower  "  combustion,"  as  he 
would  probably  be  advised  to  do  by  nine  out  of  ten  men, 
would  simply  reduce  the  temperature  of  the  fire  in  his  fur- 
nace, and  the  economical  result  would  be  about  the  same. 
His  grate  is  too  large  to  burn  coal  to  the  best  possible  ad  van- 
tage, and  his  best  remedy  is  to  reduce  its  size  and  keep  his 
fire  as  hot  as  he  can. 

This  is  not  speculation,  as  some  may  be  inclined  to  think. 
Direct  experiments  have  been  made  to  settle  the  question. 
The  grate  under  a  certain  boiler  was  tried  at  different  sizes 
with  the  following  result: 

With  grate  six  feet  long  ratio  of  grate  to  heating  surface 
was  i  to  24.4. 

With  grate  four  feet  long  ratio  of  grate  to  heating  surface 
was  o  to  36.6. 

The  use  of  the  smaller  grate  gave,  with  different  fuels  and 
all  the  methods  of  firing,  an  average  economy  of  nine  per 
cent,  above  the  larger  one,  and,  when  compared  by  burning 
the  same  amount  of  coal  per  hour  on  each,  twelve  per  cent. 
greater  rapidity  of  evaporation  and  economy  were  obtained 
with  the  smaller  grate. 

AVERAGE  BREAKING  AND  CRUSHING  STRAINS 

OF  IRON  AND  STEEL. 

Breaking  strain  of  wrought  iron  =  23  tons'") 

Crushing  strain  of  wrought  iron  =  17  tons  | 

Breaking  strain  of  cast  iron  about  7^  tons  PPer  square  inch 

Crushing  strain  of  cast  iron  =50  tons.  . . .  j       of  section. 


Breaking  strain  of  steel  bars  about  50  tons 


Crushing  strain  of  steel  bars  up  to  116  tonsj 

PITTING  OF  MUD  DRUMS. 

Mud  drums  have  frequently  been  known  to  pit  through 
their  close  connection  to  the  brick  work  with  which  they 
are  covered.  When  the  boiler  is  filled  with  cold  water,  the 
iron  will  sweat.  This  moisture  mixing  with  the  lime  of  the 
brick  work  will,  after  a  length  of  time,  injure  the  iron* 
Mud  drums  are  injured  on  the  inside  by  a  similar  chemical 
action.  The  sediments  of  lime,  etc.,  deposit  there  where 
their  action  goes  on  undisturbed  by  any  circulation.  To 
prevent  pitting  on  the  inside  from  this  cause,  blow  down  fre- 
quently, and,  on  the  outside,  keep  the  brie1*  off  the  rxlates, 
so  that  all  moisture  can  pass  off. 


i6o 
TABLE  OF  SPECIFIC  GRAVITIES. 

Weight  of  a  Cubic 
Inch  in  Lbs. 

Copper,  cast 3178 

Iron,   cast 263 

Iron,  wrought 276 

Lead ; 4103 

Steel 2827 

Sun-metal 3177 

DIVISIONS  OF  DEGREES  OF  HEAT. 

The  thermometer  is  an  instrument  for  measuring  sensible 
heat.  It  consists  of  a  glass  tube  of  very  fine  bore,  terminat- 
ing in  a  bulb.  This  bulb  is  filled  with  mercury,  and  the  top 
of  the  tube  is  hermetically  sealed  after  all  the  air  has  been 
expelled.  The  instrument  is  then  put  into  steam  arising 
from  boiling  water  and,  when  the  barometer  stands  at  thirty 
inches,  a  mark  is  placed  on  a  scale  affixed  opposite  the  place 
the  mercury  stands  at.  It  is  again  put  in  melting  ice,  and 
the  scale  again  marked.  The  space  between  these  marks  is 
divided  into  spaces  called  degrees.  In  this  country  and 
England  it  is  divided  into  180  equal  parts,  calling  freezing 
point  32°,  so  that  the  boiling  point  is  212°  ;  and  zero  or  o  is 
32°  belowfreezing  point,  and  this  scale  is  called  Fahrenheit's. 
On  the  continent  two  other  scales  are  in  use;  the  Centi- 
grade, in  which  the  space  is  divided  into  100  equal  parts, 
hence  the  name ;  and  Reaumur's,  in  which  the  space  is 
divided  into  80.  In  both  of  these  scales  freezing  point  is  o, 
or  zero  ;  so  that  the  boiling  point  of  centigrade  is  100°,  and 
Reaumur  80°. 

THE    LAW    OF    PROPORTION    IX    STEAM 
ECONOMY. 

The  basis  of  steam  engineering  science  consists  in  closely 
adhering  to  the  absolute  ratio  or  proportion  of  the  different 
parts  of  the  steam-plant,  representing  the  power  of  the  en- 
gine and  boiler  to  the  amount  of  the  work  to  be  done.  To 
use  an  extreme  illustration,  it  is  not  scientific  to  construct  a 
^hundred  horse  power  boiler  —  say  j  ,500  square  feet  of  heating 
Surface  —  to  furnish  steam  for  a  six-inch  cylinder;  nor  is  it  in 
proportion  to  use  a  cylinder  of  the  latter  size  to  drive  a 
sewing  machine.  It  may  be  said  truthfully  that  the  law  of 
true  proportion  between  boiler,  engine  and  the  desired 
amount  of  work  is  less  understood  than  almost  any  other  in 
the  range  of  mechanical  practice. 


101 

VALUABLE  INFORMATION  FOR  ENGINEERS. 

To  find  the  capacity  of  a  cylinder  in  gallons,  multiply  the 
area  in  inches  by  the  length  of  stroke  in  inches,  and  it  will 
give  the  total  number  of  cubic  inches;  divide  this  by  231, 
a:.d  you  will  have  the  capacity  in  gallons. 

The  U.  S.  standard  gallon  measures  231  cubic  inches,  and 
contains  8^  pounds  of  distilled  water. 

The  mean  pressure  of  the  atmosphere  is  usually  estimated 
at  14.7  pounds  per  square  inch. 

The  average  amount  of  coal  used  for  steam  boilers  is  12 
pounds  per  hour  for  each  square  foot  of  grate. 

•  The  average  weight  of  anthracite  coal  is  53  pounds  to  one 
cubic  foot  of  coal ;  bituminous,  about  48  pounds  to  the  cubic 
foot. 

Locomotives  average  a  consumption  of  3,000  gallons  of 
water  per  ico  miles  run. 

To  determine  the  circumference  of  a  circle,  multiply  the 
diameter  by  3. 1416. 

To  find  the  pressure  in  pounds  per  square  inch  of  a 
column  of  water,  multiply  the  height  of  the  column  in 
feet  by  .434,  approximately,  every  foot  elevation  is  equal  to 
l/2 1  pound  pressure  per  spare  inch,  allowing  for  ordinary 
friction. 

The  area  of  the  steam  piston,  multiplied  by  the  steam 
pressure,  gives  the  total  amount  of  pressure  that  can  be 
exerted.  The  area  of  the  water  piston,  multiplied  by  the 
pressure  of  water  per  square  inch  gives  the  resistance.  A 
margin  must  be  made  between  the  power  and  t"he  resistance 
to  move  the  pistons  at  the  required  speed,  from  20  to  40  per 
cent.,  according  to  speed  and  other  conditions. 

To  determine  the  diameter  of  a  circle,  multiply  circum- 
ference by  .31831. 

Steam  at  atmospheric  pressure  flows  into  a  vacuum  at  the 
rate  of  about  1550  feet  per  second,  and  into  the  atmosphere 
at  the  rate  of  650  feet  per  second. 

To  determine  the  area  of  a  circle,  multiply  the  square  of 
diameter  by  .7854. 

A  cubic  inch  of  water  evaporated  under  ordinary  atmos- 
pheric pressure  is  converted  into  one  cubic  foot  of  steam 
(approximately). 

By  doubling  the  diameter  of  a  pipe,  you  will  increase  its 
capacity  four  times. 

In  calculating  horse-power  of  tubular  or  flue  boilers,  con- 
sider 15  square  feet  of  heating  surface  equivalent  to  one 
nominal  horse-power. 


1 62 

HOW  TO  TEST  BOILERS. 

The  safe- working  pressure  of  any  boiler  is  found  by 
multiplying  twice  the  thickness  of  plate  by  its  tensile 
strength  in  pounds,  then  divide  by  diameter  of  boiler, 
then  this  result  divide  by  six.  This  gives  safe  working 
pressure. 

EXAMPLE. 

Twice  thickness  plate  X  tensile  strength -5-  diameter  of 
boiler  in  inches-5-6=safe  working  pressure  +  one-half  more 
=  maximum  test  pressure. 

Diameter  of  boiler,  60".  Thickness  of  plate,  yz", 
Tensile  strength  of  plate,  60,000  Ibs.  i "X  60,000-—  60 = 
1,000-7-6=166%  Tbs.,  which. is  the  safe  working  pressure-f 
83^  Ibs.  =  250  ft>s.,  which  is  the  maximum  test  pressure. 

After  the  safe  pressure  has  been  found  as  above,  the 
usual  way  is  to  add  one-half  more  for  a  test  pressure,  then 
apply  by  hydraulic  pressure  as  high  as  the  test  pressure,  and, 
if  the  boiler  goes  through  this  test  all  right,  it  is  safe  to 
run  it  at  two-thirds  of  test  pressure. 

Before  putting  hydraulic  pressure  on  an  old  boiler,  empty 
the  boiler,  go  over  it  carefully  with  the  hammer  for  broken 
braces,  weak  and  corroded  spots,  figure  for  safe  pressure  on 
the  thinnest  place  found  in  boiler,  fill  boiler  full  of  cold 
water,  and  gradually  heat  it  until  the  desired  pressure  is 
reached.  By  this  mode  of  testing  by  hot  water  pressure,  the 
heated  water  is  expanded,  and  is  more  elastic  than  when  cold, 
and  is  not  so  liable  to  strain  the  boiler. 

Before  allowing  the  pressure  to  be  applied,  see  that  the 
boiler  is  properly  braced  and  stayed,  and  that  the  rivets  are 
of  proper  size. 

All  flat  surfaces,  such  as  found  in  fire-box  boilers,  should 
have  stays  not  over  5  or  6  inches  apart,  for  all  ordinary 
pressure  and  boiler  heads  not  over  7  inches  apart. 

On  account  of  the  loss  of  strength  in  the  plates  by  rivet 
holes,  some  authorities  allow  only  70  per  cent,  of  the  safe 
pressure  given  above,  for  double-riveted  boilers,  and  56  per 
cent,  for  single-riveted  boilers: 

EXAMPLE. 

1 66  Tbs.  safe  pressure  in  first  example x  70  per  cent,  for 
double-rivets  =  116.20  Ibs.  safe  pressure  for  double- riveted 
boiler. 

1 66  Ibs.  safe  pressure  in  first  example  X5&  per  cent,  for 
single-riveted  seams  =92.96  Ibs.  safe  pressure  for  single- 
riveted  boilers. 


i63 
SCALE  IN  BOILERS 

Mr.  T.  T.  Parker  writes  as  follows  to  the  Amerinm 
Machinist : 

If  there  is  one  thing  more  than  another  that  the  average 
engineer  is  careful  with,  it  is  the  use  of  boiler  compounds. 
With  an  open  exhaust  heater  and  an  overworked  boiler,  and 
using  water  from  a  drilled  well  sixty  feet  deep  in  limestone,  I 
have  had  to  be  rather  careful  to  avoid  scale  and  foaming. 

I  offer  some  notes  from  my  experience  under  the  above 
conditions. 

In  using  compounds  containing  sal  soda,  I  had  to  use  40 
per  cent,  more  cylinder  oil,  and  this  invariably  reacted, 
through  the  heater  and  feed  water,  on  the  boiler,  and  pro- 
duced foaming.  I  have  used  six  compounds  warranted  to 
cure  foaming  with  above  results.  The  compounds  were 
tannic  acid  and  soda. 

Changing  to  the  use  of  crude  oil,  I  found  that  the  volatile 
parts  went  over  to  the  engine,  and  saved  loper  cent,  cylinder 
oil  over  when  using  nothing,  and  50  per  cent,  over  the  use 
of  sal  soda.  There  is  a  peculiar  easy  manner  of  making 
steam  that  is  very  different  from  the  same  boiler  using  sal 
soda.  The  results  on  scale  are  as  follows  : 

In  changing  to  a  different  solvent,  the  results  for  a  few 
runs  were  very  good,  and  then  it  seemed  to  lose  its  virtue 
while'losing  double  quantity  ;  result,  foaming.  With  crude 
oil  used  continually,  I  have  had  scale  from  one-eighth  inch 
thick,  but  never  any  thicker,  as  it  came  off  clean,  and  was 
very  porous.  I  prefer  oil  to  any  acid  or  alkali  solvent. 
For  cleaning  a  scaled  boiler  I  would  recommend  alternate 
use  of  oil  and  sal  soda,  but  the  remedy  is  heroic.  If  the 
boiler  is  not  clean  in  two  weeks,  I  miss  my  guess.  I  have 
tried  kerosene,  and  found  it  too  volatile  to  be  of  value  in  a 
limestone  district.  In  summing  up  the  results,  I  believe  : 

First  —  With  an  open  exhaust  heater,  use  only  the 
best  cylinder  oil,  which  should  be  at  least  80  per  cent, 
petroleum. 

Second  —  If  the  crude  oil  does  not  keep  the  scale  all 
out,  alternate  one  run  with  sal  soda. 

Now,  I  only  offer  this  as  my  experience,  knowing  full 
well  that  the  conditions  are  never  absolutely  the  same. 
But  I  know  of  a  plant  (in  this  city)  where  the  boiler  is  not 
worked  up  to  its  full  capacity,  and  which  is  kept  entirely 
free  from  scale,  using  hard  water,  by  the  alternate  use  of  sal 
goda  and  crude  oil. 


i64 
FUTURE  OF  THE  STEAM  ENGINE. 

The  annual  meeting  of  the  British  Association  for  the 
Advancement  of  Science,  lately  held  at  Bath,  England,  was 
opened  by  an  address  by  Sir  Frederick  Bramwell,  the  pres- 
ident of  the  association,  in  which  he  repeated  a  prediction 
made  by  him  at  a  former  meet  ing  of  the  association  regard- 
ing Ihe  displacement  of  the  steam  engine  in  the  future.  He 
said  it  was  a  sad  confession  to  have  to  make,  that  the  very 
best  steam  engines  only  utilized  about  one-sixth  of  the  work 
which  resides  in  the  fuel  that  is  consumed,  though  at  the 
same  time  it  is  a  satisfaction  to  know  that  great  economical 
progress  had  been  made,  and  that  the  six  pounds  or  seven 
pounds  of  fuel  per  horse  power  per  hour  consumed  by  the 
very  best  engines  of  Watts'  days,  when  working  with  the 
aid  of  condensation,  is  now  brought  down  to  about  one- 
fourth  of  this  consumption.  Continuing,  he  said:  At  the 
York  meeting  of  our  association  I  ventured  to  predict  that, 
unless  some  substantial  improvement  were  made  in  the  steam 
engine  (of  which  improvement,  as  yet,  we  have  no  notion), 
I  believed  its  days  for  small  powers  were  numbered,  and  that 
those  who  attended  the  centenary  of  the  British  Association 
in  1931,  would  see  the  present  steam  engines  in  museums, 
treated  as  things  to  be  respected,  and  of  antiquarian  interest, 
by  .he  engineers  of  those  days,  such  as  tlie  over-topped 
steam  cylinders  of  Newcomen  and  of  Smeaton  to  our- 
selves. I  must  say  I  see  no  reason,  after  the  seven  years 
which  have  elapsed  since  the  York  meeting,  to  regret  having 
made  that  prophecy,  or  to  desire  to  withdraw  from  it. 
The  working  of  heat  engines,  without  the  intervention  of 
the  vapor  of  water  by  the  combustion  of  the  gases  arising 
from  coal,  or  from  coal  and  from  water,  is  now  not  merely 
an  established  fact,  but  a  recognized  and  undoubted 
commercially  economical  means  of  obtaining  motive  power. 
Such  engines,  developing  from  I  to  40  horse  power,  and 
worked  by  ordinary  gas  supplied  by  gas  mains,  are  in 
most  extensive  use  in  printing  works,  hotels,  clubs, 
theatets,  and  even  in  large  private  houses,  for  the  wrorking 
of  dynamos  to  supply  electric  light.  Such  engines  are  also 
in  use  in  factories,  being  sometimes  driven  by  the  gas 
obtained  from  "  culm  "  and  steam,  and  are  given  forth  a 
horse-power  for,  it  is  stated,  as  small  a  consumption  as  one 
pound  of  fuel  per  hour.  It  is  hardly  necessary  to  remind 
you — but  let  me  do  it  —  that,  although  the  saving  of  half  a 
pound  of  fuel  per  horse-power  appears  to  be  insignificant 
when  stated  in  that  bald  way,  one  realizes  that  it  is  of  the 


I6S 

highest  importance  when  that  half-pound  turns  out  to  be 
33  per  cent,  of  the  whole  previous  consumption  of  one  of 
those  economical  engines  to  which  I  have  referred.  But, 
looking  at  the  wonderful  petroleum  industry,  arid  at  the 
multifarious  products  which  are  obtained  from  the  crude 
material,  is  it  too  much  to  say  that  there  is  a  future  for 
motor  engines  worked  by  the  vapor  of  some  of  the  more 
highly  volatile  of  these  products  —  true  vapor  —  not  a  gas, 
but  a  condensable  body  capable  of  being  worked  over  and 
over  again?  Numbers  of  such  engines,  some  of  as  much  as 
four  horse-power,  made  by  Mr.  Yarrow,  are  now  running, 
and  are  apparently  giving  good  results,  certainly  excellent 
results  as  regards  the  compactness  and  lightness  of  the 
machinery;  for  boat  purposes  ihey  possess  the  great  advan- 
tage of  being  rapidly  under  way.  I  have  seen  one  go  to- 
work  within  two  minutes  of  the  striking  of  the  match  to 
light  the  burner.  Again,  as  we  know,  the  vapor  of  this 
material  has  been  used  as  a  gas  in  gas  engines,  the  motive 
power  having  been  obtained  by  direct  combustion.  Having 
regard  to  these  considerations,  was  I  wrong  in  predicting 
that  the  heat  engine  of  the  future  will  probably  be  one  inde- 
pendent of  the  vapor  of  water?  And  further,  in  these  days 
of  electrical  advancement,  is  it  too  much  to  hope  for  the 
direct  production  of  electricity  from  the  combustion  of  fuel  ? 

GAS  FOR  LOCOMOTIVES. 

The  problem  of  obtaining  a  cheaper  fuel  than  coal  for 
locomotives,  which  has  long  bothered  railroad  men,  seems 
likely  to  be  solved  soon  by  experiments  now  being  made  with 
gds.  A  very  good  test  of  the  new  fuel  has  been  made  at  the 
works  of  the  electric  light  company  in  West  Chester,  which, 
since  the  fire  that  destroyed  the  old  plant  several  months  ago, 
have  been  dependent  for  their  motive  power  upon  the  Shaw 
locomotive.  This  is  the  engine  that  made  such  a  good  record 
in  some  trial  trips  two  or  three  years  ago,  but  which  has  never 
done  much  road  service. 

Instead  of  coal,  gns  mixed  with  air  has  been  used  in  the 
locomotive  with  e.itire  success  in  generating  sufficient  power 
to  drive  the  dynamos.  With  larger  machines  for  producing 
and  mixing  the  gas,  it  is  believed  that  power  enough  can  be 
obtained  for  driving  locomotives  with  trains,  and  a  special  car 
is  now  being  built  at  New  York  to  hold  a  large  machine  of 
the  kind  used  in  mixing  the  gas,  and  thestorage  receivers. 


1 66 

PROPORTIONS  OF  STEAM    BOILERS. 

In  a  recent  communication  to  the  Societe  Scientifique 
Industrielle  of  Marseilles,  M.  D.  Stapfer  remarked  that,  as 
he  had  never  met  with  any  good  practical  rules  for  the  pro- 
portions of  boilers  for  steam  engines,  he  had  taken  the  trou- 
ble to  examine  a  very  large  number  of  different  types,  which 
were  working  satisfactorily,  and  from  them  had  deduced  the 
following  rules :  The  water  level  in  the  boilers  of  torpedo 
boats  was  usually  placed  at  two-thirds  the  diameter  of  the 
shell,  and  in  marine,  portable  and  locomotive  boilers  at  three- 
fourths  this  diameter.  The  surface  from  which  evaporation 
took  place  should,  however,  be  made  greater  as  the  steam 

Eressure  was  reduced  —  that  was  to  say,  as  the  size  of  the 
ubbles  of  steam  became  greater.  To  produce  100  Itxs.  of 
steam  per  hour,  at  atmospheric  pressure,  this  surface  should 
not  be  less  than  7.32  square  ft.,  which  may  be  reduced  to 
1.46  square  ft.  for  steam  at  75  Ibs.  pressure,  and  0.73  ft.  for 
steam  at  a  pressure  of  150  Ibs.  It  is  for  this  reason  that 
triple-expansion  engines  can  be  worked  with  smaller  boilers 
than  were  required  with  engines  using  steam  of  lower  pres- 
sure. The  amount  of  steam  space  to  be  permitted  depends 
upon  the  volume  of  the  cylinder  and  the  number  of  revolu- 
tions made  per  minute.  For  ordinary  engines  it  may  be 
made  a  hundred  times  as  great  as  the  average  volume  of 
steam  generated  per  second.  The  section  through  the  tubes 
may  be  one-sixth  of  the  fire-grate  area  when  the  draught  is 
-due  to  chimney  from  27  ft.  to  33  ft.  high,  which  in  general 
corresponds  to  a  fuel  consumption  of  12.3  pounds  of  coal 
per  square  foot  of  grate  surface  per  hour.  This  area  may 
be  reduced  to  one-tenth  that  of  the  grate  when  forced 
draught  is  employed. 

TESTING  BOILER  PLATES. 

A  good  every-day  shop  plan  of  testing  boiler  plates  is  to  cut 
ftff  a  strip  i#  inches  wide  and  of  any  convenient  length. 
Drill  a  quarter-inch  hole,  and  enlarge  it  to  three-quarters  of 
an  inch  by  means  of  a  drift-pin  and  hammer.  If  the  plate 
shows  no  signs  of  fracture,  it  may  be  considered  of  good 
quality. 

Another  method  is  to  cut  off  a  narrow  strip,  heat  it 
to  a  cherry  red  and  cool  suddenly.  Grip  the  piece  in  a  vise, 
and  bend  it  back  and  forth  at  right  angles  by  means  of  a 
piece  of  gas  pipe  dropped  over  the  end.  The  number  of 
times  the  piece  can  stand  this  bending  is  the  measure  of  its 
quality.  A  good  piece  of  soft  steel  boiler-plate  should  s'and 
twelve  or  fifteen  bendings  without  showing  fracture. 


167 
MANIPULATION    OF   NEW  ENGINES. 

After  engines  have  been  set  up,  they  must  be  adjusted  to 
/heir  work.  It  is  not  every  man  that  can  do  this  properly, 
for  it  requires  experience  and  consideration  to  determine 
exactly  what  is  to  be  done.  A  new  engine  is  a  raw  machine, 
so  to  speak,  and,  no  matter  how  carefully  the  work  has  been 
done  upon  it,  it  is  not  in  the  same  condition  that  it  will  be 
in  a  few  weeks,  or  after  the  actual  work  it  does  has  worn 
its  bearings  smooth  and  true.  In  the  best  machine-work, 
there  are  more  or  less  asperities  of  surface,  and  very  much 
more  friction  than  than  there  will  be  later  on.  Bearings  and 
boxes  are  not  fitted  under  strain  ;  they  are  fitted  as  they 
stand,  independently  in  the  shop,  and  this  entails  a  condi- 
tion of  things  which  actual  work  may  show  to  be  faulty. 
For  this  reason  an  engineer  should  not  go  at  a  new  engine 
hammer  and  tongs,  and  try  to  suppress  at  once  every  slight 
noise  or  click  that  he  may  hear.  Neither  should  he  key  up 
solid,  or  screw  down  hard,  the  working  shafts  and  bearings, 
for  the  first  few  days.  It  is  much  better  to  let  the  things 
run  easily  for  a  while,  at  the  expense  of  a  little  noise,  rather 
than  to  risk  cutting  before  the  details  get  used  to  each  other. 
Many  good  engines  have  been  disabled  by  too  great  zeal  on 
the  part  of  those  in  charge,  when  a  little  forbearance  would 
have  been  much  better.  Pounding,  caused  by  bad  adjust- 
ment, or  valve  setting,  and  pounding  caused  by  new  bear- 
ings not  in  intimate  relation  with  each  other,  are  quite 
different  in  character,  and  a  careful  engineer  will  not  make 
haste  to  decide  upon  the  remedy  until  he  has  indicated  and 
investigated  the  engine,  and  found  out  exactly  where  the 
trouble  is.  Not  long  ago  we  saw  a  new  engine  badly  cut  in 
its  guides  from  this  very  cause  ;  a  slight  jar  was  noticed,  and 
the  engineer,  arguing  that  the  crosshead  was  the  seat  of  the 
noise,  set  out  the  gibs  so  much  that  they  seized  and  plowed 
some  bad  scores  in  the  cast-iron  guides,  which  will  always 
remain  to  remind  him  of  his  thoughtlessness.  What  has 
been  said  above  of  the  engine,  is  also  true  of  the  boiler  and 
its  appurtenances.  No  new  boiler  should  have  pressure  put 
upon  it  at  once.  Instead,  it  should  be  heated  up  slowly  for 
the  first  day,  and  whether  steam  is  wanted  or  not.  Long 
before  all  the  joints  are  made,  or  the  engine  ready  for  steam, 
the  boiler  should  be  set,  and  in  working  order.  A  slight  fire 
should  be  made  and  the  water  warmed  up  to  about  blood 
heat  only,  and  left  to  stand  in  that  condition  and  cool  off, 
and  absolute  pressure  should  proceed  by  very  slow  stages. 
Persons  who  set  a  boiler  and  then  build  a  roaring  fire  under 


i68 

It,  and  get  steam  as  soon  as  they  can,  need  not  be  surprised 
to  find  a  great  many  leaks  developed  ;  even  if  the  boiler  does 
not  actually  and  visibly  leak,  an  enormous  strain  is  need- 
lessly put  upon  it  which  cannot  fail  to  injure  it.  Of  all  the 
forces  engineers  deal  with,  there  are  none  more  tremendous 
than  expansion  and  contraction. 

TRIPLE  EXPANSIONS. 

An  interesting  example  of  the  value  of  triple  expansion 
engines,  as  compared  with  compound,  was  exhibited  on  the 
Clyde,  on  the  trial  of  the  Orient  liner  Cuzco,  which  has 
recently  been  thoroughly  renovated  and  furnished  with  new 
boilers  working  to  a  pressure  of  150  pounds  to  the  square  inch, 
and  with  triple  expansion  engines  of  the  most  approved  type, 
The  Cuzco  is  seventeen  years  old,  and  has  hitherto  been 
regarded  as  a  12%  knot  boat.  Recently  she  was  tried  on  the 
measured  mile  for  a  six-hours  run,  when  she  attained  a  speed 
of  1 6  knots,  and  made  upward  of  75  revolutions  per  minute. 
This  increase  in  speed  was,  a  daily  newspaper  correspondent 
says,  accompanied  with  the  usual  economy  in  coal  consumption, 
and  the  incident  is  remarkable  on  account  of  the  success  with 
which  the  power  of  the  new  engines  has  developed  a  high 
speed  in  a  vessel,  the  model  of  which  is  comparatively 
obsolete. 

STEAM  AS  A  CLEANSING  AGENT. 

For  cleaning  greasy  machinery  nothing  can  be  found  that 
is  more  useful  than  steam.  A  steam  hose  attached  to  the 
boiler  can  be  made  to  do  better  work  in  a  few  minutes  than 
any  one  is  able  to  do  in  hours  of  close  application.  The 
principal  advantages  of  steam  are,  that  it  will  penetrate 
where  an  instrument  will  not  enter,  and  where  anything  else 
would  be  ineffectual  to  accomplish  the  desired  result. 
Journal  boxes  with  oil  cellars  will  get  filthy  in  time,  and  are 
difficult  to  clean  in  the  ordinary  way ;  but,  if  they  can  be 
removed,  or  are  in  a  favorable  place,  so  that  steam  can  be 
used,  it  is  a  veritable  play  work  to  rid  them  of  any  adhering 
cubslance.  What  is  especially  satisfactory  in  the  use  of 
Steam,  is  that  it  does  not  add  to  the  filth.  Water  and  oil 
spread  the  foul  matter,  and  thus  make  an  additional  amount 
of  work. 


1 69 
POINTS  FOR  ENGINEERS. 

When  using  a  jet  condenser,  let  the  engine  make  three  or 
four  revolutions  before  opening  the  injection  valve,  and 
then  open  it  gradually,  letting  the  engine  make  several  more 
revolutions  before  it  is  opened  to  the  full  amount  required. 

Open  the  main  stop  valve  before  you  start  the  fires  un- 
der the  boilers. 

When  starting  fires,  don't  forget  to  close  the  gauge- 
cocks  and  safety-valve  as  soon  as  steam  begins  to  form. 

An  old  Turkish  towel,  cut  in  two  lengthwise,  is  better 
than  cotton  waste  for  cleaning  brass  work. 

Always  connect  your  steam  valves  in  such  a  manner  that 
the  valve  closes  against  t^ie  constant  steam  pressuie. 

Turpentine,  well  mixed  with  black  varnish,  makes  a  good 
coating  for  iron  smoke  pipes. 

Ordinary  lubricating  oils  are  not  suitable  for  use  in  pre- 
venting rust. 

You  can  make  a  hole  through  glass  by  covering  it  with  a 
thin  coating  of  wax  —  by  warming  the  glass  and  spreading 
the  wax  on  it,  scrape  off  the  wax  where  you  want  the  hole, 
and  drop  a  little  fluoric  acid  on  the  spot  with  a  wire.  The 
acid  will  cut  a  hole  through  the  glass,  and  you  can  shape 
the  hole  with  a  copper  wire  covered  with  oil  and  rotten- 
stone. 

A  mixture  of  one  (i)  ounce  of  sulphate  of  copper,  one- 
quarter  (#)  of  an  ounce  of  alum,  half  (y2)  a  teaspoonfitl  of 
powdered  salt,  one  (i)  gill  of  vinegar  and  twenty  (20)  drops 
of  nitric  acid  will  make  a  hole  in  steel  that  is  too  hard  to 
cut  or  file  easily.  Also,  if  applied  to  steel  and  washed  off 
quickly,  it  will  give  the  metal  a  beautiful  frosted  appear- 
ance. 

It  is  a  fact  that  thirty-five  cubic  feet  of  sea  water  is  equal  in 
weight  to  thirty-six  feet  of  fresh  water,  the  weight  being  one 
ton  (2,240  pounds). 

Remember  that  coal  loses  from  ten  (10)  to  forty  '(40)  per- 
centum  of  its  evaporative  power  if  exposed  to  the  influence 
of  sunshine  and  rain. 

Those  who  have  had  experience  think  that  for  lubricat- 
ing_purposes  palm  nut  oil  cannot  be  surpassed,  for  the  rea- 
son that  it  does  not  gum  or  waste;  neither  does  friction 
remove  it  readily  from  the  surfaces  where  it  is  applied,  and 
its  use  is  exceedingly  economical.  The  best  cylinder  oils 
produce  no  better  effect. 

If  you  are  obliged  to  make  use  of  such  a  barbarism  as  a 
rust  joint,  mix  ten  (10)  parts  by  weight  of  iron  filings,  and 


three  (3)  parts  of  chloride  of  lime  .with  enough  water  to 
make  a  paste.  Put  the  mixture  between  the  pieces  to  be 
joined,  and  bolt  firmly  together. 

Too  much  bearing  surface  in  a  journal  is  sometimes  worse 
than  too  little. 

Steel  hardened  in  water  loses  in  strength — but  hardenii-  •; 
in  oil  increases  its  strength,  and  adds  to  its  toughness. 


RAILWAY  GAUGES  OF  THE  WORLU 

jreland  has  a  standard  gauge  of  5  ft.  3  in.  ;  Spain  and 
Portugal  5  ft.  6y%  in.  ;  Sweden  and  Norway  have  the  4  ft 
8/^  in.  gauge  over  the  majority  of  their  railroads,  but  20 
per  cent  of  the  Swedish  roads  have  other  gauges,  varying 
from  2  feet  7^  in.  up  to  4  ft. 

In  Asia,  of  the  British-Indian  roads,  about  7,450  miles 
have  a  gauge  of  5  ft.  5^  in.,  the  remainder  being  divided 
among  six  gauges  from  2  ft.  to  4  ft.  Of  the  narrow  gauges, 
the  most  prevalent,  embracing  4,200  miles,  is  the  metre, 
3  ft.  3%  in.  , 

In  Japan,  with  the  exception  of  an  8-mile  piece  begun  in 
1885,  with  a  gauge  of  2  ft  9  in.,  all  the  roads  have  a  3  ft. 
6  in.  gauge. 

In  Africa,  the  Egyptian  railroads,  amounting  to  932  miles, 
are  of  the  4  ft.  8^  in.  gauge.  Algiers  and  Tunis,  with 
1,203  miles  in  1884,  had  the  4  ft.  8)4  i"-  standard  on 
all  but  155  miles,  which  had  a  3  ft.  7^  in.  gauge.  The 
English  Cape  Colony  had,  in  1885,  1,522  miles,  all  of  3  ft. 
6  in.  gauge. 

In  America,  practically  the  whole  of  the  United  States 
and  Canadian  railroads  are  of  4  ft.  8^  in.  to  4  ft.  9  in. 
gauge.  In  Mexico,  in  1884,  2,083  miles  were  4  ft.  8^  in., 
and  944  3  ft.  gauge.  In  Brazil,  at  the  end  of  1884,  there 
were  869  miles  of  5  ft.  3  in.  gauge,  and  4, 164  miles  of  various 
gauges  between  2  ft.  and  7  in.,  over  3,700  miles  being  I 
metre,  or  3  ft.  3%  in.,  or  that  this  may  be  considered  the 
standard  gauge  of  Brazil. 

In  Australia,  the  different  colonies,  rather  singularly, 
have  different  gauges,  that  of  New  South  Wales  being  4  ft. 
8^  in.,  Victoria  5  ft.  3  in.,  South  Australia  4  ft.  3  in.  and  3 
ft.  6  in.,  and  the  other  colonies  3  ft.  6  in. 

The  total  mileage  in  operation  in  the  world  at  the  end  of 
1885  was  303,048  miles.  Of  this  length,  74  per  cent,  were 
of  the  4  ft.  8>£  in.  to  4  ft.  9  in.  standard,  12  per  cent,  had 
larger  gauges,  and  14  j  er  cent,  smaller. 


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METRIC  SYSTEM 


172 

THE  MONETARY  UNITS  AND  STANDARD  COINS 
OF  FOREIGN   COUNTRIES. 

The  first  section  of  the  act  of  March  3,  1873,  provides 
"  that  the  value  of  foreign  coin,  as  expressed  in  the  money  of 
account  of  the  United  States,  shall  be  that  of  the  pure  metal 
of  such  coin  of  standard. value,"  and  that  "  the  value  of  the 
standard  coins  in  circulation  of  the  various  nations  of  the 
world,  shall  be  estimated  annually  by  the  director  of  the 
mint,  and  be  proclaimed  on  the  first  day  of  January  by  the 
secretary  of  the  treasury. 

The  estimates  of  values  contained  in  the  following  table  are 
those  made  by  the  director  of  the  mint,  Jan.  i,  1878. 


Country. 

Monetary 
Unit. 

Standard. 

Value. 

Argen  Repub.  .  . 

Peso  fuerte.  .  .  . 

Gold     

IX   C.  M. 
I      O      O 

Austria  

Florin  

Silver  

O   4.C       7 

Belgium     .    ... 

Franc  

Gold  &  Silver 

O    IQ       1 

Bolivia      .  .     . 

Dollar  

Gold  £  Silver 

£.        * 

O   QO       ? 

Brazil  

Milreis  of   1000 

British  Amer  .  .  . 
Bogota  

reis  
Dollar  
Peso  

Gold.  . 
Gold  
Gold  

o  54    5 

I      O      O 

O  Q6       C 

Central  Amer..  . 
Chili  

Dollar  
Peso  

Silver  
Gold  

o  91     8 

O  QI      2 

Cuba    

Peso  

Gold  

O  Q2       5 

Denmark  ....... 

Crown  

Gold  

o  26    8 

Ecuador  

Dollar  

O  QI      8 

Egypt  . 

Pound   of    100 

France         

piasters  .... 
Franc  

Gold  

Gold  £  Silver 

4  97    4 

O    IQ      1 

Gt   Britain    .... 

Pound  sterling 

Gold  .  . 

4.  86    ofc 

Greece       . 

Drachma  .... 

Gold  £  Silver 

O    IQ       1 

German  Emp  .  .  . 
India  

Mark   
Rupee,  1  6  an.  . 

Gold  
Silver  

o  23    8 
o  43    6 

Italv 

Lira  

Gold  £  Silver 

o  19    3 

1     y  
Japan  

Liberia  .  .  ...... 

Yen  
Dollar  

Gold  
Gold  

o  99    7 

I      O     O 

Mexico  

Dollar....  

Silver....  ..  . 

O  QQ     8 

Neitherlands  .  . 

Florin  

Silver  

Norway  .  0    ... 

Crown  

Gold  

o  26    8 

Paraguay  ...... 

Peso  

Gold  

I      O     O 

Feru  .  , 

Sol 

Silver.. 

o  06    o 

'I  UK   MONETARY  UNITS— Continued. 


Country. 

Monetary 
Umts. 

Standard. 

Value. 

Gold  

O  02      5 

Portugal  

R  ussia 

Mil.  looo  r's  .  . 
Rubles,  100  co 

Gold  

I      80 

O77     4. 

Sandwich  Islands 

Dollar  

Gold  

I      O     O 

%iin  .  . 

Peseta    of    100 

Sweden  

Switzerland  .... 
Tripoli 

centimes    .  .  . 
Crown  
Franc  
Mah.  20  v»''s 

Gold&  Sil-cr 
Gold........ 
Gold  &  Silver 
Silver  

o  19    3 
o  26    8 
o  19    3 
o  82    9. 

Tunis 

Pi's     16  car 

Silver   .    ... 

o  ii     8 

Turkey  

Piaster  ..-..., 

Gold..  

043 

Colombia      .    . 

Peso 

Silver  

o  91     8 

Uruguay  

Pat  aeon  ...... 

Gold..  

o  94    9 

DIMENSIONS  OF  AMERICAN  ENSIGNS. 


Numbers. 

Head  or 
hoist. 

Whole 
length. 

Length  of 
union. 

Feet. 

Feet. 

Feet. 

I 

19.00 

36.00 

14.40 

2 

16.90 

32.00 

12.80 

3 

14.80 

28.00 

1  1.  20 

4 

13.20 

25.00 

10.00 

5 

1  1.  60 

22.00 

8.80 

6 

IO.OO 

19.00 

7.60 

I 

8.45 
7.40 

16  oo 
14.00 

'!:£ 

9 

.12.00 

4.80 

10 

5.20 

IO.OO 

4.00 

ii 

4.20 

8.00 

3.20 

12 

3.7o 

7.00 

2.80 

13 

3.20 

6.00 

2.40 

14 

2.50 

5.00 

2.OO 

TO  DETECT  IRON  FROM  STEEL  TOOLS. 
It  is  diffiult  to  distinguish  between  iron  and  steel  tools. 
They  have  the  same  polish  and  workmanship  ;  use  will  com- 
monly show  the  difference.  To  make  the  distinction  quickly, 
place  the  tool  upon  a  stone,  and  drop  upon  it  some  diluted  nitric 
acid,  four  parts  of  water  to  one  of  acid.  If  the  tool  remains 
clean,  it  is  of  iron;  if  of  steel,  it  will  show  a  black  spot  where 
touched  with  the  acid.  These  spots  can  be  easily  rubbed  off 


174 
ARTIFICIAL  ICE-MAKING. 

Reduced  to  the  fewest  words,  the  scientific  principle  under- 
lying all  methods  for  making  artificial  ice  is  that  whenever 
a  liquid  is  evaporated  it  takes  up  more  or  less  heat  from  sur- 
rounding objects.  This  fact  can  be  easily  demonstrated  by 
any  one.  Stick  your  finger  in  your  mouth  and  moisten  it 
with  saliva.  Then  hold  the  wet  finger  in  the  wind.  At  once 
that  finger  feels  colder  than  the  rest,  for  the  moving  air 
takes  up  or  evaporates  the  moisture,  and  the  skin  gives  up 


some  of  its  heat.  It  is  an  old  scientific  trick  to  freeze  water 
in  a  fire  by  wrapping  the  bottle  with  a  rag  soaked  in  ether  or 
chloroform.  The  heat  of  the  fire  evaporates  the  highly  vola- 
tile ether  so  quickly  that  the  etlicr  sucks  all  of  the  heat  out 
of  the  water  and  freezes  it.  This  is  practically  what  the  ice 
maker  does,  only  he  uses  ammonia  or  sulphurous  oxide  in- 
stead of  ether,  and  works  on  a  large  scale  with  large  pumps, 
engines  and  miles  of  iron  pipe. 


175 

At  ordinary  temperature,  ammonia  is  a  vapor  or  gas.  The 
common  ammonia  sold  in  drug  stores  is  really  ammonia 
water  made  by  saturating  water  with  ammonia  gas.  The 
ammonia  commonly  used  in  ice-making  is  anhydrous  am- 
monia, which  is  liquid  ammonia  without  any  water  in  it. 
There  are  many  kinds  of  ice-making  machines  made,  but  all 
practically  work  on  the  same  principle. 

The  principal  part  of  the  plant  is  the  compressor  pump. 
Then  follows  the  condenser,  the  expansion  coils  and  the  re- 
ceiver. The  anhydrous  ammonia  is  received  by  the  ice- 
maker  in  oblong  iron  drums  containing  100  pounds  or  more, 
and  it  is  fed  into  the  pump  through  a  small  pipe  to  the  suc- 
tion valve  at  the  lower  end  of  the  pump,  whether  it  be  single 
or  double  acting.  The  pump  performs  a  double  office,  for 
with  one  stroke  of  the  piston  it  sucks  in  the  anhydrous  am- 
monia, and  on  the  return  stroke  compresses  the  gas  to  a 
liquid,  for  the  anhydrous  ammonia  is  used  over  and  over 
again,  first  as  liquid,  then  as  an  expanding  gas  freezing  the 
liquid,  and  then  back  as  a  liquid  again.  The  ammonia  gas 
is  liquified  not  only  by  pressure  but  by  cold.  The  pump 
forces  the  gas  into  the  condenser  first.  This  is  a  series  of 
coils  of  small  pipe  over  which  cold  water  is  constantly  flow- 
ing. The  gas  pressed  into  the  smaller  pipes  is  condensed  to 
liquid  ammonia.  As  it  condenses,  the  liquid  ammonia  flows 
into  a  storage  tank  through  small  pipes  leading  from  the 
condenser.  The  pressure  from  the  pump  and  suitable  check 
valves  force  the  liquid  ammonia  from  the  storage  tank, 
which  lies  in  a  horizontal  position,  into  two  large  vertical 
cylinders,  and  from  them  into  the  expansion  coils  which  lie 
in  the  bottom  of  the  freezing  tanks. 

Th*3  pipes  of  the  expansion  coil  are  much  larger  than  the 
pipes  in  the  condenser,  and  here  the  liquid  ammonia  expands 
or  turns  to  vapor  again,  and  as  it  evaporates  it  takes  the 
heat  from  the  salt  brine  in  the  tank  and  reduces  its  tempera- 
ture  from  18  o  above  to  10  o  below  zero,  depending  on  the 
flow  of  the  gas.  The  compressor  pump,  by  forcing  the  liquid 
ammonia  from  it  and  sucking  the  gas  towards  it,  keeps  the 
anhydrous  ammonia  moving  along  constantly,  and  it  goes 
into  the  receiver,  from  which  it  is  pumped  to  be  compressed 
and  chilled  into  a  liquid  again. 

The  ice  factories  which  use  sulphurous  oxide  instead  of 
anhydrous  ammonia  have  a  brine  made  from  magnesium 
chloride  instead  of  common  salt,  but  in  other  respects  the 


176 

system  is  about  the  same.  The  anhydrous  ammonia  and 
sulphurous  oxide  processes  are  called  the  compression 
system.  In  the  absorption  system  the  liquid  is  first  heated 
in  a  boiler  and  "the  vapor  which  is  generated  is  made  up  of 
about  9  parts  of  ammonia  gas  and  1  part  of  steam.  This 
vapor  first  passes  through  a  condenser,  where  tte  steam  Is 
turned  into  water  again,  but  as  the  temperature  is  not  low 
enough  to  liquify  the  ammonia  gas,  it  is  forced  along  by  the 
boiler  pressure  to  another  condenser.  Here  the  gas  is  con- 
densed to  a  liquid,  and  then  passes  on  to  the  expansion  coils 
just  as  it  does  in  the  compression  system.  After  doing  its 
work,  the  gas  is  brought  back  to  the  "absorber,"  where  it  is 
taken  up  by  water  again  and  pumped  back  into  the  boiler. 

In  making  artificial  ice,  the  manufacturer  wants  pure 
water.  To  be  certain  that  the  water  is  free  from  sedimeni 
and  typhoid  germs,  he  filters  and  distils  the  water  before  it 
is  frozen.  In  some  ice  works  the  water  is  filtered  once  before 
it  is  distilled,  and  twice  afterwards.  The  freezing  tanks  are 
made  of  iron.  They  usually  are  set  below  the  floor  for  the 
purpose  of  facilitating  the  handling  of  ice.  The  average 
tank  is  about  50  feet  long,  20  feet  wide  and  4  feet  deep.  The 
cans  in  which  tne  distilled  water  is  frozen  are  44  inches  by 
22  inches  by  11  inches  in  size. 

ft  The  pipes  which  carry  the  anhydrous  ammonia  go  back 
and  forth  across  the  tank  between  the  cans,  and  the  salt 
water  brine  is  kept  in  motion  by  an  agitator  something  like 
a  screw  propeller.  This  gives  the  brine  an  even  tempera- 
ture. It  requires  from  34  to  60  hours  to  freeze  a  300- pound 
cake  of  ice.  Over  the  freezing  tank  is  a  traveling  crane  with 
a  block  and  tackle  for  hoisting  the  cans  with  the  frozen 
blocks  out  of  the  tank.  The  cans  are  lifted,  so  that  when 
clear  of  the  tank  they  tilt  upside  down.  Streams  of  tepid 
water  are  directed  on  the  can,  and  in  a  short  time  the  cake 
of  ice  slips  out  of  the  can  and  slides  down  the  gangway  to 
the  ice-house. 

Nearly  every  brewery  in  the  country  has  its  own  refriger- 
ating plant.  For  cooling  cellars,  vaults  and  other  parts  of 
the  brewery,  chilled  brine  is  pumped  through  pipes.  Some- 
times, however,  as  in  the  direct  expansion  method,  the  ex- 
pansion pipes  are  used.  Both  methods  are  also  employed  in 
chemical  works,  cold  storage  warehouses  and  packing 
houses.  Ice  machines  are  rated  with  capacities  varying  from 
50  to  100  tons  of  ice  a  day.  They  are  built  vertical  and  hori- 


177 

zontal,  single  or  duplicate,  operated  either  direct  or  from 
an  engine. 

NOVEL  USES  OF  COMPRESSED  AIR. 

Most  people  think  that  compressed  air  is  only  used  for 
automatic  car-brakes  and  rock  drills.  The  fact  is,  com- 
pressed air  as  an  agent  for  transmitting  energy  and  power 
is  pushing  electricity  hard  and,  on  some  lines,  has  distanced 
steam. 

On  many  railroads  compressed  air  has  taken  the  place  o( 
whisk  brooms  and  beaters  for  cleaning  seat  cushions  of  pas- 
senger cars.  The  air  at  50  to  75  pounds  pressure  to  the 
square  inch  is  brought  into  the  car  through  an  air  hose 
which  has.  a  brass  air  nozzle  on  the  end.  The  women  handle 
this  nozzle  as  though  water  instead  of  compressed  air  were 
coming  through,  and  the  air  jet  drives  the  dust,  cinders  and 
dirt  out  of  the  cushions  quicker  and  better  than  any  other 
method. 

In  the  new  criminal  court  building  of  Chicago,  a  system  of 
pneumatic  clocks    has  been  installed.    The  "master"  clock 
sends  pulsations  of  compressed  air  through  small  pipes  to  : 
the  connecting  clocks,  and  thus  all  run  on  the  same  time  uiv1 
are  regulated  together. 

In  several  machine  shops  in  the  country  there  is  not  a  belt 
or  a  piece  of  shafting  outside  of  the  engine-room.  Instead, 
pipes  run  from  the  compressed  air  reservoir  to  compressed 
air  motors.  Each  drill,  lathe,  reamer,  milling  machine, 
emery  wheel,  bending  rolls,  punch,  drop  hammer  and  press 
has  its  individual  air  motor  or  engine,  and  the  mere  turning 
of  a  throttle  valve  starts  or  stops  the  machine. 

The  pneumatic  clock  system  was  installed  first  in  Paris 
about  1870.  From  it  grew  the  present  compressed  air  cen- 
tral-power system,  which  supplies  over  10,000  horse-power 
to  users  in  the  French  capital.  It  is  there  used  for  all  pur- 
poses, from  running  clocks  to  operating  dynamos  for  elec- 
tric lights.  The  central  station  furnishes  air  at  a  pressure 
of  75  pounds  to  the  square  inch. 

Asphalt  used  for  street-paving  is  refined  by  compressed  air. 
In  its  original  shape,  just  as  it  comes  from  Trinidad,  asphalt 
is  too  soft  for  street-paving,  and  is  not  homogeneous  To 
refine  it,  the  asphalt  is  boiled  in  kettles  for  three  or  four 
days,  and  while  the  heat  is  on  it  must  be  stirred.  Pipes  hav- 


178 

ing  numerous  holes  are  placed  in  the  bottom  of  the  kettle, 
and  while  the  asphalt  is  boiling,  compressed  air  is  forced 
through  the  pipes  and,  escaping  through  the  holes,  agitates 
the  thick  black  material,  thus  refining  it. 

Compressed  air  was  the  paint-brush  which  placed  the  color 
on  the  World's  Fair  buildings  in  Chicago,  and  which  to-day 
is  painting  railroad  bridges  and  corrugated  iron  plates  for 
buildings.  The  compressed  air  not  only  draws  the  liquid 
paint  from  the  tubs  or  buckets,  but  sprays  it  over  the  sur- 
face and  drives  it  into  the  wood. 

In  the  big  shipyards,  where  the  government  vessels  are 
built,  all  the  calking  is  done  by  compressed  air.  and  one  com- 
pressed air  calking  machine  does  the  work  of  four  men. 
TLis  calker  strikes  1.000  blo\vs  a  minute.  The  same  tool  is 
used  by  boiler-makers,  and.  in  a  modified  form,  by  stone- 
cutters for  dressing  an  i  carving  stone.  The  little  engine 
which  does  the  work  is  in  the  handle  of  the  tool  which  is 
about  the  size  of  a  larne  chisel  handle.  Tiie  air  is  brought 
to  the  tool  by  a  small  rubber  pipe,  which  is  so  flexible  it  can 
be  handled  easily  and  at  any  angle.  A  piston  and  spring 
shove  the  tool  in  and  out,  and  it  can  be  so  adjusted  that  the 
heaviest  or  most  delicate  work  can  be  done  with  it. 
*  Acids  which  would  eat  a  pump  up  at  once,  are  raised  by 
compressed  air.  Sewage  which  is  below  the  level  of  the 
sewer  is  forced  up  by  compressed  air.  Impure  water  is 
cleaned,  gold  and  silver  are  dug  from  mines,  letters  are 
copied  in  the  letter  press,  elevator  signal  bells  are  rung, 
cattle  are  lifted  after  being  killed  in  slaughter  houses,  fur- 
nace grates  are  shaken,  crude  oil  is  atomized  under  steam 
boilers,  grain  is  cleaned,  and  a  hundred  other  things  are 
daily  done  by  compressed  air. 

CONCERNING  ELECTRIC  BATTERIES. 

In  a  general  way  batteries  are  divided  into  two  classes- 
open  circuit  batteries  and  closed  circuit  batteries.  In  all 
kinds  of  batteries  the  electro-motive  force  decreases  and  the 
internal  resistance  increases  when  working  on  a  circuit  of 
low  resistance.  This  is  caused  by  "polarization,"  which  is 
the  collecting  of  tiny  bubbles  of  hydrogen  gas  on  the  nega- 
tive plate  due  to  the  action  of  the  current.  These  bubbles 
covering  the  negative  plate  not  only  diminish  the  working 
surface  of  the  plate,  and  thus  reduces  the  electro-motive 


179 

f.>rce.  but  increases  the  re>ist,ince.  In  this  condition  the 
battery  is  said  to  be  polarized.  To  correct  this  evil  various 
chemicals,  either  fluid  or  solid  are  placed  in  the  battery  to 
generate  oxygen  which  may  unite  with  the  hydrogen.  Such 
chemicals  are  called  "depolarizers."'  Those  batteries  in 
which  the  depolarizers  act  slowly  and  after  the  buttery  has 
stopped  work  are  called  "open  circuit1':  that  in  which  the 
depolarizers  is  working  is  "closed  circuit."  The  open  circuit 
battery  is  used  where  the  demand  for  the  current  is  inter- 
mittant:  the  "closed  circuit  battery"  is  used  where  the  cur- 
rent is  required  almost  continuously. 

Batteries  should  be  kept  where  the  temperature  is  about 
even,  avoiding  extremes  of  heat  or  cold.  They  should  be 
carefully  protected  from  dust  and  dirt.  The  cells  should  be 
covered  so  as  to  prevent  rapid  evaporation  of  the  solution. 
The  best  place  for  batteries  is  a  dry  cool  place. 

\Vhere  zinc  is  used  in  a  battery  the  plate  should  be  rolled 
and  not  cast  zinc.  The  carbon  plates  should  be  solid,  fine 
and  hard.  Those  made  from  gas-retort  carbon.  The  upper 
part  of  carbon  rods  should  be  dipped  in  melted  paraffiine 
until  the  wax  has  soaked  in,  say  to  an  inch  or  so  from  the 
top.  This  will  keep  the  solution  from  "creeping"  or  crawl- 
ing up,  as  it  will  do  unless  the  rod  is  waxed.  Before  a  zinc 
rod  is  placed  in  a  battery  it  should  first  be  thoroughly 
brightened  by  scouring  it  with  weak  sulphuric  acid,  and  then 
a  small  portion  of  mercury  should  be  rubbed  over  it.  The 
amalgamation  will  prevent  what  is  known  as  "local  action." 
Sal-ammoniac,  if  used,  should  be  pure,  otherwise  the  battery 
will  become  dirty.  Porus  cups  should  be  soaked  in  water 
and  then  thoroughly  scrubbed  out.  Carbon  plates,  in  renew- 
ing batteries,  should  be  treated  in  the  same  way.  Batteries 
should  never  be  neglected  if  good  work  from  them  is  desired. 
A  poor  battery  is  often  worse  than  no  battery  at  all,  and  it  is 
false  economy  to  re-charge  with  impure  and  therefore  cheap 
chemicals. 

HOW  BOILER  PLATES  ARE  PROVED. 

This  is  done  by  placing  a  piece  of  Bessmer  steel  10  inches 
long  in  a  testing  machine.  Gradually  the  surface  scales  off 
in  the  middle,  to  become  smaller  in  area,  and  somewhat 
elongated,  til.  at  last,  it  breaks  with  a  sharp  snap  at  a  break- 
ing strain  of  about  28  tons  to  the  square  inch,  the  reduction 
of  area  bein«r  51  per  cent,  and  the  elongation  23  per  cent. 


i  So 

DIFFERENCES  OF  TIME    FROM  NEW  YORK. 
At  any   Given    Time  hi  New    York  it  is  in 

HKS.    MIN.    SKC. 

Amsterdam  (Holland) 5  16          later. 

Berne  (Switzerland) 5  26 

Berlin  ( Prussia) 5  49     *  -     " 

Brusses  (Belgium). ... 5  13     30     u 

Buda  Pesth  (Hungary) 6  12 

Carlsruhe  ( Baden) 5  30 

Qhristiania  (Norway) 5  39 

Cologne  (Germany) 5  2  j. 

Constantinople  (Turkey) 6  52 

Copenhagen  (Denmark) 5  46 

Dublin  (Ireland) 4  30     30     " 

Frankfort  (Germany) 5  30 

Geneva  (Switzerland) 5  23     30     " 

Gothenburg  (Sweden) 5  45 

Greenwich  (England) 4  56 

Hamburg  (Germany) 5  36 

Lisbon  (Portugal) ,       ....     .    ..    ....  4  19     30     '• 

London  (England) 4  5  >     5^     *" 

Madrid  (Spain) 4  41      15     u 

Moscow  (Russia) 7  26  " 

M  unich  ( Bavaria) 5  42     30     " 

Naples  (Italy) ?, . . .  5  53 

Paris  (P>ance) 5  05     15     " 

Prague  (Austria) 5  54  " 

Rome  (Italy) 5  46  " 

St.  Petersburg  ( Russia) 6  57  " 

Stuttgart  ( Witrtemberg) . , 5  33  " 

Stockholm  (Sweden) 6  08  " 

Trieste  (Austria) 5  51 

Venice  (Italy) 5  45     30    " 

Vienna  (Austria 6  01     33     " 

Warsaw  (Poland) 6  20    '        " 

The  differences  are   at   the   rate  of  one  hour    for  every 
fifteen  degrees  of  longitude,  or  four  minutes  for  each  degree. 

A  VALUABLE  PRESERVATIVE  PAINT. 
Soapstone  incorporated  with  oil,  after  the  manner  of  paint, 
is  said  to  be  superior  to  any  kind  of  a  paint  as  a  preservative. 
Soapstone  is  to  be  had  in  an  exceedingly  fine  powder,  mixes 
readily  with  prepared  oils  for  paint,  which  covers  well  surfaces 
of  iron,  steel,  or  stone,  and  is  an  effectual  remedy  against 
rust. 


TIME  AT  DIFFERENT   PLACES,  WHEN  IT  IS 
O'CLOCK  AT  NEW  YORK  CITY;  ALSO,  DIF- 
FERENCE IX  TIME  FROM  NEW  YORK. 


New  York  City  12  M. 

Fast. 

Slow. 

Places. 

II 

12 
II 
12 
II 
12 
12 
II 
I  I 
II 
I  I 
II 
II 
12 
II 
12 
12 
II 
12 
II 
12 
II 
10 
II 

4 
ii 

12 
10 
II 
12 
12 
12 
12 
10 
II 
II 
IO 

MS 

p.m 

a.  m. 
}.m 
a.m. 
p.m 

a.m. 

p.m 
a.m. 
p.m 

a.m. 
p.m 
a.m. 
p.m 
a.m. 

a.  m. 

« 

p.m 
a.m. 
p.m 

a.  m. 

« 

p.m 
« 

u 

a.m. 

!    « 

11 

M 

.: 

„ 

u 

IO 

28 

II 
41 

5 
43 

10 

5 

i 

12 

4 

S 

II 

M 

9 

10 

'9 

23 
54 
4i 
3i 
36 

36 

42 
u 

3i 

22 

41 

46 

4 

55 

4 

20 

9 

27 

56 

27 

40 
42 

£ 

24 

12 

10 

40 
20 
10 

56 

12 

3* 

37 

16 
H 

56 

Albany,  N.  Y  
Annapolis,  Mel  

1    l 

5°   4 
1  6  40 

4933 
20  52 
ii  46 
4020 
36  18 
529 
18   2 
2836 
23  4» 

10;    4 

2350 
28l6 
I132 
I7|20 

4i:33 
48  '40 

5  r7 
2850 

37    4 
1848 

4356 
H 
1044 
5528 
423 
536 
148 
1218 
418 
56| 
3944 
5046 
32    4 

4 

I 
40 

52 
46 

if 

32 

33 
i7 

$( 
44 

36 
48 
ft 

18 

i 

i 

i 

1: 

Augusta,   Me  

Baltimore  Md  

Buffa'o,  NY  

Charleston   S.  C     

Chicago,  111  

Cleveland,  O..  .  .        

Detroit,  Mich-  

Fall  River,  Mass  

Frankfort,  Ky  

Halifax,  N.  S  

Harrisburg,  Pa  

Hartford,  Conn  

Key  West,  Fla  

Leavenworth,  Kan  

Liverpool,  Eng.  

Lowell    j^lass  

Milwaukee,  Wis  

Montpelier,  Yt  

Montreal,  Que..              

New  Bedford,  Mass   

New  Haven,  Conn  

New  Orleans,  La   

Niagara  Falls,  N.  Y.  

Norfolk,  Ya  

Omaha,  Neb  

1 82 

TIME  AT   DIFFERENT   PEACES.— Continued. 


New  York  City  12  M. 

I 
II 

"as 
M 

t. 
S 

S 
II 

lo\\ 
M 

10 

4 

4 
24 

*9 
13 
9 

32 

13 

28 

8 

21 

'  2 
12 

S 

Places. 

II 

M 

s 

u 

5 
ii 

9 
u 

12 
12 
12 
II 
II 

8 

9 

8 
1  1 

12 
10 
II 
II 
II 
II 

49 

5 
55 
56 
35 
15 

10 

ii 

40 

46 
50 

27 
46 
3i 

5 
54 
5i 

38 
57 

A7 

36 
21 
20 

52 
2 

25 
II 
48 
10 

9 

36 
13 

39 

37 
59 

12 

27 

24 
/|8 

« 

]).  m 
a.  m  . 

p.  in 

C( 

a.m. 

u 

p.  m 
a  m. 

5 

5 

15 

10 

ii 

5 

21 

2 

25 
II 

37 

2 

3 

2 

3 

I 

24 
40 

8 

12 
50 
51 

24 

47 

21 

I 

48 

33 
36 

12 

Paris,  France  

Philadelphia,  Pa  

Pike's  Peak,  Col  

?ittsburg,  Pa  

Portland,  Me  
Providence,  R.  I  

Quebec,  Oue   

Raleigh,  N.  C  

Richmond,  Va  

Salt  Lake  City,  Utah.    .    .  . 

San  Francisco,  Cal 

Savannah,  Ga.  .        

St.  Loui-,  Mo.          

Syracuse,  N.  Y.. 

Toronto,  Ont.    .  .          

Trenton,  N.    J  
Washington,  D.  C..  . 

4.ENGTII    AND     NUMBER    OF    TACKS    TO    THE 
POUND. 


Title. 

Length. 

No.  p.  Ib. 

Title. 

Length. 

No.  p.  Ib. 

I      oz. 

Y*       in- 

16,000 

10        OZ. 

11-16 

1,  600 

1/2    " 

3-i6      ' 

10,666 

12          ' 

¥ 

^333 

2         " 

X      ' 

8,000 

14          * 

13-16 

I»i43 

?.y*  " 

5-i6      ' 

6,400 

16       < 

H 

1,000 

6      " 

X      ' 

5>333 

.18       « 

15-16 

888 

4 

7-16     ' 

4,000 

20       ' 

I 

800 

6       " 

9-16      ' 

2,666 

22          ' 

11-16 

727 

8       " 

%    ' 

2,000 

24         ' 

i>* 

666 

SWITCHING  FROM  THE  ENGINE  CAB. 

A  device  that  will  enable  the  engineer,  from  his  cab,  to 
switch  his  locomotive  at  pleasure,  while  the  conductor  on 
the  caboose  or  rear  car  closes  the  switch  again,  would  surely 
be  a  novelty  in  railroading,  amounting  to  a  revolution.  Yet 
a  Cleveland  inventor  claims  to  have  solved  the  problem,  and 
to  be  able  to  demonstrate  its  practicability  with  a  working 
model.  Not  to  go  into  the  details,  it  may  be  sufficient  to 
say  that  the  "  central  throw  "  switch  is  shifted  by  a  double- 
flanged  shoe,  of  any  length,  dropped  from  beneath  any  front 
or  rear  truck,  while  the  train  is  in  motion,  first  overthrowing 
the  crank  that  draws  the  lock-plate  off  the  fixed  rail,  then 
moving  the  lug  of  the  angle  connected  with  the  fly-rail  to  the 
right  or  left,  as  indicated  by  the  target  on  the  engine  or 
caboose,  after  which  the  lock  slides  forward  and  grasps  the 
fixed  rail,  holding  the  "  fly  "  in  alignment,  making  a  continuous 
rail.  Thus,  a  switch  is  carelessly  left  open,  ai.d  a  passenger 
train  is  approaching.  The  engineer  detects  the  danger  ;  the 
improvised  "  shoe  "  is  dropped  to  the  rail ;  it  strikes  the  lug, 
the  switch  is  closed,  and,  a  collision  avoided.  On  the  other 
hand,  a  train  may  be  side-tracked  by  the  same  simple 
operation  from  the  cab.  Of  course,  this  would  do  away  with 
switchmen  and  frog  accidents,  and  a  great  many  other  disad- 
vantages incident  to  the  present  method,  should  the  invention 
come  into  practical  use.  This,  necessarily  is  yet  to  be  dem- 
onstrated by  actual  test,  under  varying  conditions,  before 
success  can  be  confidently  claimed  ;  but  the  device  is  certainly 
of  general  interest. 

RAILROAD  SIGNALS. 

The  following  signals,  taken  from  the  "  Standard  Code," 
are  in  use  on  a  majority  of  American  railroads.  Explanation: 
O  means  short,  quick  sound;  — means  long  sound. 

Apply  brakes,  stop O 

Release  brakes O  O 

Back O  O  O 

Highway  crossing  signal —  . —  O,  or  O  O 

Approaching  stations —  blast  lasting  five  C3& 

Call  for   switchman O  O  O  O 

Cattle  on  track ^~~- 

Train  has  parted —  O 

For  fuel O  O  O  Op 

Bridge  or  tunnel  warning a  *  O  O  —  • 

Fire  aiarm c ,   —  O  O   0   3 

Will  take  side  track.  .  —  —  ,  , 


184 
MANILLA  KOPE  TRANSMISSION. 

A  four-strand,  hard-laid  manilla  rope,  having  a  core,  or 
"heart-yarn,"  is  probably  the  best  rope  for  transmission  pur- 
poses, although  three-strand  rope  is  generally  recommended, 
says  a  writer  in  the  American  Miller.  Of  course  it  is  im- 
portant to  have  the  rope,  laid  in  tallow,  as  that  greatly  pro- 
longs its  life.  The  matter  of  splice  is  also  important.  Sea- 
men all  agree  that  the  long  splice  is  the  best,  but  the  expe- 
rience of  rope-transmission  men  is  almost  universally  in 
favor  of  a  short  splice.  The  length  of  a  long  splice  in  an 
inch  diameter  rope  will  be  five  or  si  x  feet,  while  a  short  one 
is  two  and  two  and  a  half  feet.  I  think  this  is  what  the 
sailors  term  "a  short  splice."  I  have  seen  a  short  splice  suc- 
ceed where  long  ones  have  repeatedly  failed.  I  have  known 
of  a  manilla  rope  used  out  of  doors  being  painted  with  oil, 
and  then  varnished.  It  seems  to  work  well.  Tar  is  certainly 
unsuitable  as  a  dressing  for  transmission  rope.  In  the  first 
place  it  weakens  it;  in  the  second,  its  sticking  to  the  pulley 
or  sheave  would  be  a  detriment  rather  than  an  improvement. 
There  is  no  difficulty  about  the  ropes  sticking  on  the  sheave, 
if  properly  designed  and  constructed. 

SAFE  WORKING   PRESSURE   FURNACE   FLUES. 

In  a  report  to  his  company,   the  chief  engineer  of  the 
Engine,  Boiler  and  Employers'  Liability  Insurance  Company, 
purposes  the  following  rule  for  the  safe-working  pressure  for 
cylindrical  furnaces  in  fines  :  Safe-working  pressure 
50/2     d 


where 

/=thickness  of  plate  in  thirty-second  of  au  inck. 
/=length  of  flue  in  feet. 
//=diameter  in  inches. 

RIVETLESS  STEEL  SLEEPERS. 
^Mr.  H.«  Hipkins  has  invented  a  rivetless  steel  sleeper  for 
railroads.  The  lips  or  jaws  for  holding  the  rails  in  place  are 
stamped  out  of  the  solid  plate,  and  are  stiffened  by  corruga- 
tions or  brackets,  which  are  also  raised  from  the  solid  plate 
out  of  the  hollow  at  the  back  of  each  jaw.  A  center  strip 
is  provided  for  the  rail  to  rest  upon,  dispensing  with  all  rivets 
and  loose  parts.  These  sleepers  can  be  laid  rapidly,  and  they 
are  claimed  to  be  especially  adapted  to  use  underground  in 
mines 


TAKE    CARE    OF    YOUR    AUTOMATIC    SPRINK- 
LERS. 

Ma"}*  business  blocks,  workshops,  stores,  etc.,  have  been 
expensively  fitted  up  with  automatic  sprinklers  as  a  safeguard 
against  fires,  a  certain  temperature  of  heat  fusing  the  metal, 
opening  a  valve  and  letting  on  a  flow  of  water.  But  an  in- 
spection of  th3  perforated  pipes  in  a  majority  of  instances  will 
reveal  the  fact  that  the  apparatus  has  been  neglected.  Cob- 
webs and  dust  cover  the  pipes,  the  sprinklers  have  been  per- 
mitted to  corrode  and  unsolder,  and,  should  a  fire  chance  to 
occur  and  the  friendly  services  of  the  sprinklers  ever  be 
required,  they  would  l.e  found  almost  useless,  and  for  all  the 
work  they  would  perform  in  the  line  of  throwing  cold  water 
on  the  devouring  elements,  the  premises  might  as  well  have 
remained  l<  unprotected. " 

HOW  TO  OVERCOME  VIBRATION. 

How  to  put  the  smith  shop  in  an  upper  story  without 
having  the  working  on  the  anvils  jar  the  building,  has  been  a 
problem  that  has  frequently  given  manufacturers  trouble.  A 
mechanical  engineer  says  it  may  be  safely  done  by  placing  a 
good  heavy  foundation  of  sheet  lead  on  the  floor,  and  on  that 
putting  a  good  thickness  of  rubber  belting. 

Another  person  who  is  interested  in  the  problem  has  tried 
the  experiment,  with  some  success,  of  placing  the  block,  not 
on  the  floor,  but  on  the  joist  direct,  making  a  cement  floor  up 
to  the  block,  and  over  the  wooden  floor,  reaching  back  beyond 
the  reach  of  sparks.  It  is  sometimes  said  that  blacksmith 
shops  never  burn,  but  they  keep  right  on  burning  in  spite  of 
theory,  and  cement  floors  ought  to  be  helpful  in  guarding 
against  fires. 

BOILER   EXPLOSIONS  IN  GERMANY. 

In  Germany,  during  1887,  there  were  thirteen  boiler 
explosions,  the  Germans  making  up  in  destructiveness  what 
they  lack  in  numbers  of  these  accidents. 

By  the  thirteen  explosions,  seventeen  persons  were  killed; 
five  seriously,  and  fifty-nine  slightly  injured.  One  of  these 
explosions  was,  so  far  as  known,  the  most  destructive  that 
ever  occurred.  A  battery  of  twenty-two  boilers,  at  the  blast 
furnaces  of  Friedenshutte,  Silesia,  exploded,  completely 
demolishing  the  boiler-house,  setting  fire  to  a  number  of 
other  houses  by  throwing  red-hot  bricks,  killing  ten  persons, 
and  wounding  fifty-two. 


i86 
ALLOYS    AND    SOLDERS. 


ALLOYS. 

H 

1) 

a. 
a, 
o 
U 

G 

N 

Antimony. 

-i 

V 

Bismuth.  1 

Brass  enjjine  bearmfs 

13 
15 

25 

112 

100 

1  60 

14 
15 

5 

Tough  brass,  engine  work.  .  .  . 
"        for  heavy  bearings  .... 
Yellow  brass   for  turning. 

Bell  metal                        

16 
i 

i 

Brass  locomotive  bearings.  .  .  . 
"      for  straps  and  glands.  . 
Munt/'s  sheathing  

7 
F') 

64 

I  }O 

6 

i 
i 

4 

........ 

Metal  t  •')  expand  in  cooling.  .  . 

2 

9        1 

i 
9° 

I 

5 

2 

3 

7 

1  l< 

.  .  •  • 

:::: 

Statuary  bronze  

2 

Type  m^tal     from 

"               to 

j 

SOLDERS, 

For  lead 

"    tin 

2 

2 

I 

^ 
i 

i 

3 

"        "        (hard) 

"        "        (soft)    

I 
2 

«           u                a 

I 

HOW   TO    MAKE    HARD    AND    DUCTILE    BRASS 
CASTINGS. 

Two  per  cent,  by  weight  of  finely  pounded  bottle  glass, 
placed  at  the  bottom  of  the  crucible  in  which  red  brass  is 
being  melted  for  castings,  gives  great  hardness,  and  at  the 
same  time  ductility  to  the  metal.  Porous  castings  are  said  to 
be  almost  an  impossibility  when  this  is  done,  and  the  product 
is  likely  tc  V  of  great  service  in  parts  of  machinery  subject  to 
strain.  An  addition  of  one  per  cent,  of  oxide  of  manganese 
facilitates  working  in  the  lathe  and  elsewhere  where  great 
hardness  might  be  an  objection. 


1*7 

DECIMAL  EQUIVALENTS 
of  8ths,  i6ths,  32ds  and  64ths  of  an 


Inch. 


tractions  Decimals 

Fractions  Decimals 

of  an     of  an 

of  an     of  an 

Inch.     Inch. 

Inch.     Inch. 

1-64  =  .015625 

33-64=  .515625 

1-32  =  .03125 
3-64  =  .046875 

17-3  =03125 
35-64  =  .546875 

1-16  =  .0625 

9-16  =  .5625 

5-64  =  .078125 

37-64  =0/8125 

3-32  =  .09375 

19-32  =  -59375 

7-64=  -109375 

39-64  =  .609375 

#  =  .125 

H  =  .625 

9-64  =  .140625 

41-64  =  .640625 

5-32  =  .15625 
11-64=  .171875 

21-32  =  .65625 
43-64=  -671875 

3-16=  .1875 

11-16  =  .6875 

13-64=  .203125 

45-64  V.  -703*25 

7-32  =.21875 

23-32  =  .7185 

15-64  =  .234375 

47-64  =.734375 

X  =  -5 

^  =  •75 

17-64  =  .265625 

49-64=  .765625 

9-32  =  .28125 
19-64  =  .296875 

25-32  =  -78125 
51-64=  .796875 

5-16  =.3125 

13-16  =  .8125 

21-64  —  -328125 

53-64=  .828125 

1  1-32  =  .34375 

27-32  =  .84375 

23-64  =  .359375 

55-64  =  .859375 

H  =  -375 

%  =  -875 

25-64=  •  390625 

57-64  =  .89625 

13-32  =  .40625 

29-32  =  .90625 

27-64  =  .421895 

59-64=  .921871 

7-16  =  .4375 

15-16  =  .9375 

29-64=  .453*25 

61-64  =  .953125 

15-32  =  .46875 
31-64=  .484375 

X  =  -5 

31-32=  .96875 
63-64  =  -984375 

HOW  TO  ANNEAL  SMALL  TOOLS. 

A  very  good  way  to  anneal  a  small  piece  of  tool  steel  is  to 
heat  it  up  in  a  forge  as  slowly  as  possible,  and  then  take  two 
fireboards  and  lay  the  hot  steel  between  them  and  screw  them 
in  a  vice.  As  the  steel  is  hot,  it  sinks  into  the  pieces  of 
wood,  and  is  firmly  imbedded  in  an  almost  air-tight  charcoal 
bed,  and  when  taken  out  .cold  will  be  found  to  be  nice  and 
soft.  To  repeat  this  will  make  it  as  soft  as  could  be  wished. 


1 88 
AN  EXPERIMENT  WITH  A  LOCOMOTIVE. 

A  locomotive  engineer  who  takes  an  intelligent  interest 
in  operating  his  engine  economically,  relates  the  particulars 
of  runs  where  careful  efforts  were  made  to  test  the  differ- 
ence in  the  consumption  of  coal  that  resulted  with  the  re- 
verse lever  hooked  back  as  far  as  practicable  and  the  throttle 
full  open,  and  running  with  a  late  cut-off,  and  the  steam 
throttled,  or  the  difference  between  throttling  and  cutting  off 
short. 

First  Case — A  train  of  19  loaded  and  12  empty  cars, 
rated  at  25  loads.  Run  from  Mansfield  to  Lodge,  distance, 
8.6miles,  nearly  level.  Forced  the  train  into  speed,  and  then 
pulled  the  reverse  lever  to  the  center  notch,  and  opened  the 
throttle  wide.  The  engine  jarred  a  good  deal,  due,  doubtless, 
to  the  excessive  compression,  but  the  speed  was  maintained. 
Twenty-two  minutes  were  occupied  by  the  run,  a  speed  of 
23  miles  per  hour,  and  17  shovelfuls  of  coal  M'eie  con- 
sumed in  keeping  up  steam.  By  weighing,  it  was  found  a 
shovelful  averaged  14  pounds,  making  the  coal  used  per 
train  mile  average  27.7  pounds. 

Second  Case — A  train  of  25  loads  and  six  empties,  rated 
as  28  loaded  cars.  Ran,  as  in  the  first  case,  from  Mansfield 
to  Lodge.  Pulled  the  train  into  speed  in  as  nearly  as  possi- 
ble the  same  time  as  in  the  previous  test,  but,  when  the 
speed  was  attained,  kept  the  reverse  lever  in  the  nine-inch 
notch,  and  throttled  the  steam  to  keep  down  the  speed. 
Although  the  train  was  rated  two  loads  heavier  than  the  pre- 
vious one,  it  consisted  mostly  of  merchandise,  while  the 
other  was  heavy  freight,  and  handled  decidedly  easier.  Hav- 
ing pulled  both  trains  over  40  miles  before  arriving  at  Mans- 
field, there  was  full  means  of  judging  which  was  the  easier 
train  to  handle. 

The  run  was  made  in  24  minutes,  two  minutes  longer 
than  in  the  other  case,  and  32  shovelfuls  of  coal  were  used, 
being  at  the  rate  of  52  pounds  per  train  mile.  In  both 
instances  the  fire  was  as  nearly  as  possible  the  same  depth  at 
the  beginning  and  end  of  the  run. 

Our  correspondent  thus  concludes  his  narrative:  "  It  is 
interesting  to  know  that  on  the  first  occasion  238  pounds  of 
coal  were  used  to  do  the  same  work  in  less  time  than  448 
pounds  were  required  to  do  under  the  changed  circumstances 
of  the  second  trip;  showing  that  a  gain  of  88  per  cent,  may 
be  effected  by  running  with  full  throttle  and  early  cut  off."' 


1 89 

FAST  AMERICAN    STEAMERS. 

The  following  is  a  list  of  twenty-eight  fast  American 
steamers  of  from  2,200  to  4,000  tons,  all  of  which  have 
shown  a  sea  speed  of  more  than  fifteen  knots  for  six  consecu- 
tive hours,  and  from  which  would  be  made  the  selection  of 
vessels  to  be  held  in  reserve  for  cruisers: 

Vessels.  Hailing  Port.  Tonnage.  Speed. 

Newport New  York 2,735  17-9 

City  of  Augusta Savannah .2,870  16.5 

City  of  Puebla New  York .2,624  16.5 

Queen  of  the  Pacific. . .  .Portland,  Or 2,728  16.5 

Alameda .Philadelphia 3,158  16.5 

Mariposa San  Francisco 3*158  16.5 

State  of  California San  Francisco 2,266  16 

Alliance New  York 2,985  16 

Louisiana New  York .. . . , 2,840  16 

Ohio Philadelphia 3,126  15.6 

Saratoga New  York 2,426  15.4 

City  of  Alexandria New  York 2,480  15.4 

Nacoochee Savannah 2,680  15.4 

Chattahoochee New  York 2,676  15.4 

Roanoke  ...  , New  York 2,354  15.4 

Excelsior. New  York 3,264  15.4 

Alamo New  York       2,943  15.4 

Lampasas New  York 2,943  15.4 

SlPaso New  York 3,531  15.4 

El  Dorado San  Francisco  ....  .3,531  15-4 

H.  F.  Dimock Boston .2,625  15.4 

Herman  Winter Boston 2,625  15.4 

Seminole New  York 2,557  15.4 

El  Monte New  York 3,53*  J5-4 

San  Pedro New  York 3, 119  15.4 

San  Pablo New  York. 4,064  15.4 

Cherokee New  York 2,557  15 

Santa  Rosa New  York. -.2,417  "*> 

A  WARNING  TO  ENGINEERS. 

.  Never  take  the  cap  off  a  bearing  and  remove  the  upper 
brass  to  see  if  things  are  working  well,  for  you  never  can 
replace  the  brass  exactly  in  its  former  position,  and  you  will 
find  that  the  bearing  will  heat  soon  afterward,  on  account 
of  your  unnecessary  interference.  If  there  is  any  trouble, 
you  will  find  it  out  coon  enough. 


190 
WEIGHT  AND  AREAS  OF 

SQUARt  &  ROUND  BARS  OF  WROUGHTIRON 

And  Circumference  of  Round  Bars. 

One  cubic  foot  weighing  480  Ibs. 


i 

Thickaesa 

Weight  of 

Weight  of 

irea  of 

irea  of 

CirflUnftlWH 

r  Diameter 

CD  Baj 

O  B« 

CD  B« 

O  Bar 

of  Q  Btf 

IQ  laches. 

Oaa  Foot  long. 

On9  Foot  long 

;n  sq  inches. 

m  sq.  inahea. 

miaehes. 

O 

.013 

.010 

.OO39 

.0031 

.1963 

1, 

.052 

.041 

.0156 

.O123 

.3927 

ft 

.117 

.092 

.0352 

.0276 

.5890 

} 

.208 

.164 

.0625 

.0491 

.7864 

ft 

.326 

.256 

.0977 

.O767 

.9817 

.469 

.368 

.1406 

.11O4 

1.1781 

A 

.638 

.501 

.1914 

.15O3 

1.3744 

* 

.833 

.654 

.2500 

.1963 

1.5708 

A 

1.056 

.828 

.3164 

.2485 

1.7671 

t 

1.3O2 

1.O23 

.39O6 

.3O68 

1  9635 

fi 

1.576 

1.237 

.4727 

.3712 

2  1598 

1 

1.875 

1  473 

.6625 

.4418 

2  3662 

if 

2.2O1 

1.728 

.6602 

.5185 

2  6625 

2.552 

2.0O4 

.7656 

.6013 

2.7489 

U 

2.93O 

2.3O1 

.8789 

.6903 

2.9452 

1 

3.333 

2.618 

1.0000 

.7854 

3.1416 

A 

3.763 

2.955 

1.1289 

.8866 

33379 

i 

4.219 

3.313 

1.2656         .9940 

36343 

A 

4.7O1 

3.692 

1.4102 

1  1075 

373O6 

i 

5.208 

4.091 

1.5625 

1.2272 

3.9270 

A 

5.742 

4.510 

1  7227 

1  3530 

4  1233 

i 

6.302 

4.950 

1.8906 

1  4849 

43197 

A 

6.888 

5.410 

&OQ64 

1.6230 

4.5160 

i 

7.500 

5.89O 

2.2600 

1  7671 

4  7124 

8.138 

6.392 

2.4414 

1.9175 

4.9O87 

¥ 

8.802 

6.913 

2.64O6 

2.0739 

5.1051 

H 

9.492 

7.455 

2.8477 

2.2365 

6.3O14 

i  ' 

10.21 

8.018 

3.0625 

24053 

6.4978 

H 

1O.95 

8.601  - 

3.2852 

2.5802 

5.6941 

11.72 

9.2O4 

3.5156 

2.7612 

5.89O5 

H 

12.51 

9.828 

3.7539 

2.9483 

,6.0868 

SQUARE  AND  ROUND  BARS. 

(CONTINUED.) 


Ttttknea 
v  Diameter 
in  Inches, 

Weight  of 
QBar 
One  Foot  long. 

Weight  of 

O  *" 

One  Foot  long. 

ire*  of 

in  sq.  inches. 

ire*  of 

O  B» 

in  sq.  inchea 

3.1416 
3.341O 
3.5466 
3.7583 

GrcnmfannM 
in  inches. 

2 

! 

13.33 
14.18 
15.05 
15.95 

10.*47 
11.14 
11.82 
12.63 

4.0000 
4.2539 
4.5156 
4.7852 

6.2832 
6.4795 
6.6759 
6.8722 

| 

j* 

16.88 
17.83 
18.80 
<L9.8O 

13.25 
14.OO 
14.77 
16.55 

6.O625 
6.3477 
5.64O6 
6.9414 

3.9761 
4.2OOO 
4.4301 
4.6664 

7.0686 
7.2649 
7.4613 
7.6578 

it 

2O.83 
21.89 
22.97 

24.08 

16.36 
17.19 
18.O4 
18.91 

6.250O 
6.5664 
6.89O6 
7.2227 

4.9O87 
6.1672 
5.4119 
5.6727 

7.854O 
8.O5O3 
8.2467 
8.4430 

I 

25.21 
26.37 
27.65 
28.76 

19.8O 
20.71 
21.64 
22.69 

7.6625 
7.9102 
8.2656 
8.6289 

5.9396 
6.2126 
6.4918 
6.7771 

8.6384 
8.8357 
9.O321 
9.2284 

3 

! 

30.00 
31.26 
32.65 
33.87 

23.66 

24.65 
25.67 
26.60 

9.0000 
9.3789 
9.7656 
10.16O 

7.0686 
7.3662 
7.6699 
7.9798 

9.4248 
9.6211 
9.8173 
10.014 

| 

36.21 
36.68 
37.97 
39.39 

27.65 
28.73 
29.82 
30.94 

1O.563 
10.973 
11.391 
11.816 

8.2958 
8.6179 
8.9462 
9.28O6 

10.21O 
10.4O7 
10.6O3 
1O.799 

! 

40.83 
42.30 
43.80 
45.33 

32.O7 
33.23 
34.40 
35.60 

12.25O 
12.691 
13.141 
13.598 

9.6211 
9.9678 
10.321 
1O.68O 

10.996 
11.192 
11.388 
11.585 

H 

46.88 
48.45 
60.05 
61.68 

36.82 
38.O5 
39.31 
40.59 

14.O63 
14.535 
15.O16 
15.5O4 

11.O45 
11.416 
11.793 
12.177 

11.781 
11.977 
12.174 
12.37O 

192 


SQUARE  AND  ROUND  BARS. 


>r  DiuoeUr 
Afl  Inches. 

Weigh:  of 
D  B« 
One  Koot  long. 

63.33 
65.O1 
66.72 
68.46 

We:?ht  of 

Das  *'no:  long. 

O*f 

in  ^.  inches. 

4re»  of  . 
t    O   Bar 
in  sq.  inches. 

of  O   Bar 

in  inches. 

4 
ji 

A 

41.89 
43.21 
44.55 
45.91 

1G.OOO 
16.5O4 
17.016 
17.535 

12.566 
12.962 
13.364 
13.772 

12.566 
12.763 
12.959 
13.155 

T5 

60.21 
61.99 
63.8O 
65.64 

47.29 
48.69 
60.11 
61.55 

18.O63 
18.598 
19.141 
19.691 

14.180 
14.607 
15.O33 
15.466 

13.352 
13.548 
13.744 
13.941 

1 
H 

67.60 
69.39 
71.3O 
73.24 

63.01 
64.60 
£6.00 
67.52 

20.25O 
20.816 
21.391 
21.973 

15.904 
16.349 
16.800 
17.267 

14.137 
14.334 
14.53Q 
.14.72(3 

1 

75.21 
77.20 
79.22 
81.26 

69.07 
60.63 
32.22 
63.82 

22.563 
23.160 
23.766 
24.379 

17.721 
18.19O 
18.665 
19.147 

14.923 
15.119 
15.315 
15.512 

s 

83.33 
85.43 
87.65 
89.70 

65.45 
67.10 
68.76 
70.45 

25.00O 
25.629 
26.266 
26.910 

19.635 
20.129 
2O.629 
21.135 

157O8 
15.9O4 
16.1O1 
16.297 

I 

91.88 
94.08 
96.30 
98.55 

72.16 
73.89 
75.64 
77.4** 

27.563 
28.223 
28.891 
29.666 

21.648 
22.166 
22.691 
23.221 

16.493 
16.69O 
16.886 
17.082 

A 

A 

100.8 
103.1 
106.5 
IO7.8 

79.19' 
81.00 
82.83 
84.69 

3O.250 
30.941 
31,641 
32.348 

23.758 
24.3O1 
24.85O 

25.400 

17.279 
17.475 
17.671 
17.868 

y 

it 

11O.2 
112.6 
116.1 
117.F 

86.56 
88.45 
90.36 
92.29 

33.063 
33.785 
34.516 
35.254* 

25.967 
26.635 
27.10G 
27.688 

18.O64 
..18.261 

18.653 

193 


SQUARE  AND  ROUND  BARS. 

(CONTINUED) 


.  —  ,  .  .  — 

4 

^•kiifJS 

We.pht  of 

I     Weight  of 

ire*  of 

inn  of 

Circumferan* 

fcimetei 

G  •- 

O  B»< 

QBar 

0   Bar 

of  O  Bw> 

Inches. 

One  Foot  long 

Oae  foot  long. 

in  sq.  incbas. 

in  sq.  inches 

in  inch**. 

3 

120.0 

94.25 

36.00O 

28.274 

18.85O 

122.5 

96.22 

36.754 

28.806 

19.O46 

¥ 

125.1 

98.22 

37.516 

29.465 

19.242 

127.6 

10O.2 

38.285 

30.O69 

19.439* 

130.2 

102.3 

39.063 

30.680 

19.635 

, 

132.8 

1O4.3 

39.848 

31.296 

19.831 

•i 

135.5 

106.4 

4O.641 

31.910 

20.028 

A 

138.1 

1O8.5 

41.441 

i    32.548 

20.224 

.   4 

•I 

14O.8 

110.6 

42.250 

33  183 

20.420 

143.6 

112.7 

43.O66 

33.824 

20.617 

146.3 

1149 

43.891 

34.472 

2O.813 

H 

149.1 

117.1 

44.723 

35.125 

21.000 

f  * 

151.9 

119.3  " 

45.663 

35785 

21.206 

4.1 

154.7 

121.5 

46.410 

36.450 

21.402 

l| 

157.6 

123.7 

47.266 

37.122 

21.598 

160.4 

126.0 

48.129 

37.800 

21,79$ 

i 

. 

i 

163.3 

128.3 

49.000 

38.485 

21,90* 

166.3 

13O.6 

49.879^ 

39.175 

-22.187 

u  f 

169.2. 

132.9 

50.766 

39.871 

13s 

172.2 

135.2    . 

51.660 

40.674 

22.'58O 

i* 

175.2 

137* 

52  563 

41.282 

22.777 

1$L 

178.2 

14O.O 

63^473 

41.997 

22.973 

t 

181.3 
184.4 

142.4 
144.8 

64.391 
55.318 

'42.718 
43.446 

23.160 
23.366 

I 

187.5 

147.3 

56.25O 

44.179 

23.662 

iV 

190.6 

149.7 

67.191 

44.918 

23.758 

f 

193.8 

152.2 

68.141 

45.664 

23.955 

197.0 

154.7 

59.098 

46.415 

,24.151 

f 

500.2 

157.2 

60.063 

47.173 

24.347 

H 

203.5 

159.8 

61.O35 

47.937 

24.544 

1 

2O6.7 

162.4 

62.O16 

48.707 

24.74O 

il 

210.0 

164.9 

63.0O4 

49.483 

24.030 

194 


SQUARE  AND  ROUND  BAfcS. 

(CONTINUED.) 


feekam 

n  Inches. 

One  Foot  long 

Weight  of 
QBar 
One  foot  long 

Arctof  " 
in  sq.  inches. 

Area  of 
O  Bar 
in  sq.  inches. 

Cireiunferenc* 
of  O  **f 

8 

213.3 

167.6 

64.000 

50.265 

26.133 

A 

216.7 

170.2 

65.004 

61.O54 

25.329 

i 

220.1 

172.8 

66.O10 

51.849 

25.525 

A 

223.5 

175.5 

67.035 

62.649 

25.722 

'i 

226.9f 

J78.2 

68.063 

53.456 

25.918 

ft 

23O.3 

180.9 

69.098 

54.269 

26.114 

i 

23Q.8 

183.6 

70.141 

65.088 

26.311 

A 

237.3 

186.4 

71.191 

65.914 

26.6O7 

Fi 

1* 
240.8 

189.2 

72.260 

56.745 

26.704 

!  (, 

244.4 

191.9 

73.316 

67.583 

26.9<X> 

fY 

248.0 

194.8 

74.391 

58.426 

27.096 

251.6 

197.6 

75.473 

69.276 

27.293 

1 

255.2 

200.4 

76.563 

60.132 

27.489 

'11 

258.9 

203.3 

77.660 

60.994 

27.685 

ft 

262.6 

206.2 

78.766 

61.862 

27.882 

H 

266.3 

2O9.1  - 

79.879 

62.737 

28078 

v 

*• 

m* 

0) 

9 

270.0 

J2121  ' 

81.000 

63.617 

28.274 

273.8  1 

215.0  r 

82.129 

64.5O4 

28.471 

I  i  I 

277.61 

218.0 

83.266 

65.397 

28.667 

Al 

281.41 

221.O 

84.410 

66.296 

28.863 

IT" 

^285.2 

224.O 

85.563 

67.201 

29.060 

'A 

289.1 

.227.0. 

t  86723 

68.112 

29.256 

293.0 

230.1 

187JB91 

69.029 

29.452 

A' 

296.9 

233.2 

P9.066 

69.953 

29.649 

|» 

300.8 

236.3  "• 

90.250 

70.882 

29.845 

1 

3O4.8 
308.8 
312.8 

239.4 
242.5  I 
2*5.7 

91.441 
r  92.641 
93.848 

71.818 
72.76O 
73.7O8 

3O.O41 
30.239 

30.434. 

I 

316.9 

248.9 

95.063 

74.662 

30.63r 

ft- 

321.0 

252.1 

96.285 

75.622 

3o]827j 

1- 

325.1 

255.3 

97.516 

76.589 

31.O23 

It 

329.2 

1 

258.5 

98.754 

77.561 

§1.220 

195 


SQUARE  AND  ROUND  BARS. 

(CONUINUED.) 


iiekaess 

Duuaetw 

T  
Weight  of 

On*  Foot  long. 

Weight  of 
QB*r 
On*  Foot  long. 

ATM  of 

in  iq.  inches. 

ireiof 

OB- 

in  sq.  inches. 

CircuoftraM 
of  O  B«* 

in  inchM. 

0 

333.3 

261.8 

100.00 

78.540 

31.416 

1*5 

^37.5 

265.1 

1O1.25 

79.525 

31.612 

£ 

341.7 

268.4 

1O2.52 

80.616 

31.8O9 

A 

346.0 

271.7 

103.79 

81.513 

32.005 

* 

350.2 

275.1 

105.06 

82.516 

32.201 

A 

354.5 

>  78.4 

106.36 

83.625 

32.398 

I 

358.8 

28i.8 

107.64 

84.641 

32.694 

A 

363.1 

285.2 

1O8.94 

85.662 

32.79O 

i 

367.5 

288.6 

'   \  10.26 

86.590 

32.987 

A 

371.9 

292.1 

1O1.57        87.624 

33.183 

1 

376.3 

295.5 

112.89        88.664 

33.379 

a 

380.7 

299.0 

114.22       89.710 

33.576 

i 

385.2 

302.5 

115.56 

90.763 

33.772 

it 

389.7 

306.1 

116.91 

,  V821 

33.968 

i 

394.2 

309.6 

118.27 

92.386 

34.166 

H 

398.8 

313.2 

119.63 

93.966 

34.361 

f 

L 

403.3 

318.8 

121.00 

95.033 

i  S4.568 

X 

407.9 

320.4 

122.38 

96.116 

34.764 

| 

412.6 

324.0 

123.77 

97.2O6 

34.^50 

nr 

417.2 

327.1/ 

126.16 

98.301 

35.147 

1 

421.9 

331.3 

126.56 

99.402 

35.343 

A 

426.6 

335.O 

127.97 

10O.61 

35.539 

| 

431.3 

333.7 

129.39 

kOl.62 

35.736 

A 

436.1 

342.5 

130.82 

102.74 

35.932 

i 

440.8 

346.2 

132.25 

1O3.87 

36.128 

A 

445.6 

35O.O 

133.69 

105.00 

36.325 

1 

450.6 

353.8 

135.14 

106.14 

36.521 

H 

455.3 

367.6 

136.60 

107.28 

36.717 

f 

460.2 

361.4  . 

.  138.06 

108.43 

36.914 

H 

465.1 

365.3- 

139.64 

109.59 

37.11O 

| 

470.1 

369.2 

141.02 

11O.75 

37.3O6 

** 

475.0 

373.1 

142.60 

111.92 

37,503 

196 

Weight  of  Sheets  of  Wrought  Iron,  Steel  Cop* 
per  and  Brass.     (From  Haswell.) 

er  Square  Foot.     Thickness  by  Birmingham  Gauge. 


"•O.rf 

^ftagai 

Thickness 
in  inches. 

Iron. 

Steel. 

copy. 

Brass. 

0000 

.454 

18.22 

18.46 

20.57 

19.43^ 

t  ooo 

.425 

17.05 

17.28 

19.25 

18.19 

>00 

.38 

15.25 

15.45 

17.21 

16.26 

o 

.34 

13.64 

13.82 

15.4O 

14.55 

1 

.3 

12.04 

12.20 

13.59 

12.84 

2 

.284 

11.40 

11.55 

12.87 

12.16 

3 

.259 

10.39 

10.53 

11.73 

11.09 

4 

.238 

9.55 

9.68 

10.78 

10.19 

6 

.22 

8.83 

8.95 

9.97 

9.42 

6 

.203 

8.15 

8.25 

9.20 

8.69 

7 

.18 

7.22 

7.32 

8.15 

7,70 

8 

.165 

6.62 

6.71 

7.47 

,7,06 

,0 

.148 

5.94 

6.02 

6.70 

6.33 

10 

.134 

6.38 

6.45 

6.07 

6.74 

11 

.12 

4.82 

4.88 

5.44 

6.14 

12 

.109 

4.37 

4.43 

4.94 

4.67 

13 

.095 

3.81 

3.86 

4.30 

^4.07 

14 

.083 

3.33 

3.37 

3.76 

3.55 

15 

.072 

2.89 

2.93 

3.26 

3.08 

16 

.065 

2.61 

2.64 

2.94 

2.78 

17 

.058 

2.33 

2.36 

2.63 

2.48 

(18 

.049 

1.97 

1.99 

2.22 

2.10 

19 

.042 

4.69 

171 

.90 

1.80 

20 

.035 

1.40 

1.42 

.59 

1.60 

21 

.032 

1.28 

1.3O 

.45 

1.37 

.22 

.028 

1.12 

1.14 

.27 

1.20 

'23 

.025 

1.00 

1.02 

.13 

1.07 

24 

.022 

.883 

.895 

.00 

.942 

25 

.02 

.803 

.813 

.906 

.856 

26 

.018 

.722 

.732 

.815 

.770 

27 

.016 

.642 

.651 

.725 

.685 

28 

.014 

.662 

.569 

.634 

.599 

29 

.013 

.522 

.529 

.589 

.556 

30 

.012 

.482 

.488 

.544 

.514 

31 

.01 

.401 

'.407 

.453 

.428 

32 

.009 

.361 

.360 

.408 

.385 

33 

.008 

.321 

.325 

.362 

.342 

34 

.007 

.281 

.285 

.317 

.300 

35 

.005 

.201 

.203 

.227 

.214 

Specific  Gravity, 

7.704 

7.806 

8.698 

8.218 

Weight  Cubic  Foot, 

481.25 

487.75 

543.6 

613.6    A 

"    Inch, 

.2787 

.2823 

314$ 

.297? 

i97 


Weight  of  Sheets  of  'Wrought  Iron,  Steel,  Cop- 
per and  Brass.     From  Haswell. 

Weight  per    Square    Foot.     Thickness   by   American   (Brown  oc 
Sharpen)  Gauge. 


la  of 
fa*g* 

thickness 
in  inches. 

Iron. 

Steel. 

Copper. 

Brass. 

oooo 

.46 

18.46 

18.7O 

20.84 

19.69 

000 

.4096 

16.44 

16.66 

18.56 

17.53 

00 

.3648 

14.64 

14.83 

16.53 

15.61 

0 

.3249 

13.04 

13.21 

14,72 

13.90 

1 

.2893 

11.61 

11.76 

13.11 

12.38 

2 

.2576 

10.34 

10.48 

11.67 

11.03 

3 

.2294 

9.21 

9.33 

10.39 

9.82 

4 

.2043 

8.20 

8.31 

9.26 

8.74 

5 

.1819 

7.30 

7.40 

8.24 

7.79 

6 

.1620 

6.50 

6.59 

7.34 

6.93 

7 

.1443 

5.79 

5.87 

6.54 

6.18 

8 

.1285 

5.16 

5.22 

5.82 

5.50 

9 

.1144 

4.59 

4.65 

5.18 

4.9O 

1O 

..1019 

4.09 

4.14 

4.62 

4.36 

11 

.0907 

3.64 

3.69 

4.11 

3.88 

12 

.0808 

3.24 

3.29 

3.66 

3.46 

13 

.0720 

2.89 

2.93 

3.26 

3.08 

14 

.0641 

2.57 

2.61 

2.90 

2.74 

15 

.0571 

2.29 

2.32 

2.69 

2.44 

16 

,0508 

2.04 

2.07 

2.30 

2.18 

17 

.O453 

1.82 

1.84 

2.05 

1.94 

18 

.0403 

1.62 

1.64 

1.83 

1.73 

19 

.0359 

1.44 

1.46 

1.63 

1.54 

20 

.032O 

1.28 

1.30 

1.45 

1.37 

21 

.0285 

1.14 

1.16 

1.29 

1.22 

22 

.O253 

1.02 

1.03 

1.15 

1.08 

23 

.0226 

.906 

.918 

1.02 

.966 

24 

.0201 

.807 

.817 

.911 

.860 

25 

.0179 

.718 

.728 

.811 

.766 

26 

.0159 

.640 

.648 

.722 

.682 

27 

.0142 

.570 

.577 

.643 

.608 

28 

.0126 

.507 

.514 

.573 

.541 

29 

.0113 

.452 

.458 

.510 

.482 

3O 

.O10O 

.402 

.408 

.454 

.429 

31 

.0089 

.358 

.363 

.404 

.382 

32 

.0080 

.319 

.323 

.360 

.340| 

33 

.0071 

.284 

.288     .321 

.303 

34 

.O063 

.253 

.256     .286 

.270 

35 

.0056 

.225 

.221  j   .254 

.240; 

I98 

WEIGHTS    OF   FLAT    ROLLED  IRON  PER 

LINEAL  FOOT. 
For    Thicknesses    from    1-16    in.    to   2   in.,   and 

Width  from  i  in.  to  12^  in. 
Iron  weighing  480  Ibs.  per  cubic  foot. 


fUeknesf 

la  laches. 

1" 

w 

IK" 

w 

2" 

w 

2K" 

2V< 

12" 

A 

208 

260 

.313 

.365 

.417 

.409 

-521 

.573 

2.50 

i 

.417 

.521 

.625 

.729 

.833 

.938 

1.C4 

1.15 

5.CO 

A 

.625 

.781 

.938 

1.09 

1.25 

1.41 

1.56 

1.72 

7.CO 

.833 

1.04 

1.25 

1.46 

1.67 

1.88 

2.08 

2.29 

10.00 

A 

1.04 

1.30 

1.56 

1.C2 

2.08 

2.34 

2.GO 

2.8G 

12.60 

i 

1.26 

1,56 

1.88 

2.19 

2.LO 

2.81 

8.13 

3.44 

15.CO 

A 

1.46 

1.82 

2.19 

2.55 

2.92 

3.28 

8.C5 

4.01 

17.50 

* 

1.67 

2.08 

2.50 

2.92 

3.33 

3.75 

4.17 

4.58 

20.00 

& 

1.88 

2.34 

2.81 

3.28 

8.75 

4.22 

4.C9 

5.16 

22.50 

ft 

2.08 

2.60 

8.13 

3.C5 

4.17 

4.C9 

6.21 

5.73 

25.CO 

2.29 

2.86 

3.44 

4.01 

4.58 

5.16 

6.73 

6.SO 

27.50 

jl 

2.50 

3.13 

3.75 

433 

5.00 

5.G3 

625 

6.88 

30.CO 

II 

2.71 

339 

4.06 

474 

5.42 

6.09 

6.77 

7.45 

"kco 

i 

2.92 

3.G5 

4.38 

5.10 

6.83 

6.56 

719 

802 

33.CO 

3.13 

3.91 

4.69 

5.47 

6.25 

703 

7.81 

8.59 

87.50 

i 

3.33 

4.17 

6.00 

5.83 

6.67 

7.60 

8.33 

9.17 

40.00 

i& 

8.54 

4.43 

5.31 

6.20 

7.08 

7.97 

8.85 

9.74 

42.50 

u 

3.75 

4.69 

5.63 

6.56 

7.50 

8.44 

9.38 

10.31 

45.00 

3.% 

4.95 

5.94 

6.93 

7.92 

8.91 

9.90 

10.89 

47.50 

u 

4.17 

5.21 

6.25 

7.29 

8.33 

9.38 

10.42 

11.46 

50.00 

I* 

4.37 

5.47 

6.56 

7.G6 

8.75 

9.84 

10.94 

12.03 

52.60 

if 

4.58 

6.73 

6.88 

8.02 

9.17 

10.31 

11.46 

12.60 

55.00 

til 

4.79 

5.99 

7.19 

8.39 

9.58 

10.78 

11.98 

13.18 

57.50 

U 

5.00 

625 

7.50 

8.75 

10.00 

11.25 

12.50 

13.75 

60.00 

IT'S 

5.21 

6.51 

7.81 

9.11 

10.42 

11.72 

1302 

1432 

62.50 

If 

5.42 

6.77 

8.13 

9.48 

10.83 

12.19 

13.54 

14.90 

65.00 

Ifl 

5.63 

7.03 

8.44 

9.84 

1125 

12.66 

14.06 

15.47 

67.50 

5.83 

7.29 

8.75 

10.21 

11.67 

13.13 

14.58 

16.04 

70.00 

Hi 

6.04 

7.55 

9.06 

10.57 

12.08 

13.59 

15.10 

16.61 

72.50 

If 

625 

7.81 

9.38 

10.94 

12.50 

14.06 

15.63 

17.19 

75.00 

tf* 

6.46 

8.07 

9.69 

11,30 

12.92 

14.53 

16.15 

1776 

77.50 

8 

6.67 

8.33 

10.00 

11.67 

13.33  '15.00 

16.67 

18.33 

80.00 

199 


WEIGHT    OF    FLAT    ROLLED    IRON    PE* 
LINEAL  FOOT. 

(CONTINUED.) 


Thickness 
IB  Inebn. 

3" 

1 

3'i" 

3X» 

4"    4^" 

4tJ 

4%"' 

is- 

rs 

.625 

.677:     729 

.781 

833 

.885 

.938 

.990 

2.50 

5 

1.25 

1.35 

1  46 

1.56 

167 

1.77 

1.88 

1.98 

5.00 

A 

1.88 

2.03    2.19 

234 

250 

2.66 

2.81 

2.97 

7.50 

V 

2.50 

2.71 

2.92 

8.13 

333 

3.54 

3.75 

396 

10.00 

^ 

313 

339 

3.65 

3.91 

417 

4.43 

4.69 

4.95 

12.50 

t 

375 

406 

48g 

469 

600 

5.31 

563 

5.94 

15.00 

*  ? 

4.38 

474 

6.10 

6.47 

6.83 

0.20 

6.56 

6.93 

17.50 

i 

5.00 

5.42 

6.83 

6.25 

6.67 

7.08 

7.50 

7-92 

20.00 

A 

6.63 

6.09 

6.56 

7.03 

750 

797 

844 

8.91 

22.50 

•I 

6.25 

6.77 

7.29 

7.81 

8.33 

8.85 

938 

9.90 

25.00 

6.88 

7.45 

8.02 

8.59 

9.17 

9.74 

10.31 

0.89 

27.50 

1 

7.50 

8.13 

8.75 

9.38 

10.00 

10.63 

1155 

1.88 

30.00 

41 

8.13 

8.80 

948 

10.16 

10.83 

11.51 

12.19 

2.86 

32.50 

| 

8.75 

948 

10.21  i  10.94 

11.67 

12.40 

13.13 

3.85 

35.00 

i! 

9.38 

10.16 

10.94 

11.72 

12.50 

13.28 

14.06 

4.84 

37.50 

10.00 

10.83 

11.67 

12.50 

13.33 

14.17 

15.00 

15.83 

40.00 

f& 

1063 

11.51   12.40 

13.28 

14.17- 

L5.05 

15.94 

6.8g 

42.50' 

** 

11.25 

12.19 

13.13 

14.06  15.00 

15.94 

10.88 

17.81 

45.00 

11.88 

12.86 

13.85 

14.84  15.83 

1&82 

17.81 

18.80 

47.50 

^ 

12.50 

13.54 

14.58 

15.63 

16.C7 

17.71 

18.75 

19.79 

50.00 

13.13 

14.22 

15.31 

15,41 

17.50 

18.59 

19.C9 

20.78 

52  oO 

j'a 

13.75 

1490 

16.04 

17.19 

18.33 

19.48 

20.63 

21.77 

65'.00 

1T75 

14.38 

15.57 

16.77 

17.97 

19.17 

20.36 

21.56 

22.76 

57.50 

15.00 

16.25 

17.50 

18.76 

20.00 

21.25 

22.50 

23.75 

60,00 

1TV 

15.63 

16.93 

18.23 

19.53 

20.83 

22.14 

23.44 

24.74 

C2.50' 

16.25 

17.60 

18.96 

20.31 

21.67 

23.02 

24.33 

25.73 

65.00 

pi 

16.88 

18.28 

19.69 

21.09 

22.50 

23.91 

25.31 

26.72 

07.60 

«i 

17.50 

18.95 

20.42 

21.88 

23.S3 

24.79 

26.25 

27.71 

70.00 

« 

18.13 
18.75 
19.38 

19.C4 
20.31 
20.99 

21.15 
21.88 
22.60 

22.66 
23.44 

24.22 

£4.17 
25.00 
25:83 

25.C8 
26.56 
27.45 

27.19 
28.13 
29.06 

23.70 

29.ca 

30.C3 

72.00 
75.00 
77.59 

2 

20.00 

21.67 

23.33 

25.00  J26.67 

28.33 

30.00 

01.07 

CO.OO 

WEIGHTS    OF   FLAT    ROLLED  IRON  PER 
LINEAL  FOOT. 

(CONTINUED.) 


thickness 

fc  Inches, 

5" 

a*- 

w 

~~ 

G" 

«H«X" 

w 

12" 

A 

1.04 

1.09 

1.15 

1.20 

1.25 

1.30 

1.35 

1.41 

2.50 

2.08 

2.19 

2.29 

2.40 

2.50 

2.60 

2.71 

2.81 

5.00 

I*? 

3.13 

3.28 

3.44 

3.59 

3.75 

8.9i 

4.06 

4.22 

7.50 

\ 

4.17 

4.38 

4.58 

4.79 

5.00 

5.21 

5.42 

5.63 

10.00 

^ 

5.21 

5.47 

573 

599 

6.25 

6.51 

6.77 

7.03 

12.50 

Y 

6.25 

6.56 

6.88 

7.19 

7.50 

7.81 

8.13 

8.44 

15.00 

7.29 

7.66 

8.02 

8.39 

8.75 

9.11 

9.48 

9.84 

17.50 

y 

8.33 

8.75 

9.17 

9.58 

10.00 

10.42 

10.83 

11.25 

20.00 

A 

9.38 

9.84 

10.31 

1078 

11.25 

11.72 

12.19 

12.66 

22.50 

10.42 

10.94 

11.46 

1198 

12.50 

13.02 

13.54 

14.06 

25.00 

H 

11.46 

12.03 

12.60 

1318 

13.75 

14.32 

14.90 

15.47 

27.50 

4 

12.50 

13.13 

13.75 

14.38 

15.00 

15.63 

16.25 

16.88 

30.00 

H 

13.54 

14.22 

1490 

15.57 

16.25 

16.93 

17.60 

18.28 

32.50 

14.58 

1531 

16.04 

16.77 

17.50 

18.23 

18.96 

19.69 

35.00 

H 

15.63 

16.41 

17.19 

17.97 

18.75 

19.53 

20.31 

21.09 

37.50 

16.67 

17.50 

1833 

1917 

20.00 

20.83 

21.67 

22.50 

4000 

1 

i  A 

17.71 

18.59 

19.48 

20.36 

21.25 

22.14 

23.02 

23.91 

42.50 

18.75 

19.69 

20.63 

21.56 

22.50 

23.44 

24.38 

25.31 

45.00 

i^ 

19.79 

20.78 

2177 

22.76 

23.75 

24.74 

25.73 

26.72 

47.50 

1  i 

20.83 

21.88 

22.92 

23.96 

25.00 

26.04 

27.08 

28.13 

50.00 

l£ 

21.88 

22.97 

24.06 

25.16 

26.25 

27.34 

28.44 

29.53 

52.50 

^  ! 

22.92 

24.06 

25.21 

26.35 

27.50 

28.65 

29.79 

30.94 

55.00 

!A 

23.96 

25.16 

26.35 

27.55 

28.75 

29.95 

31.15 

82.34 

57.50 

25.00 

26.25 

27.50 

28.75 

30.00 

31.25 

32.50 

83.75 

60.00 

IT'* 

26.04 

27.34 

28.65 

29.95 

31.25 

32.55 

33.85 

35.16 

62.50 

M 

27.08 

28.44 

29.79 

31.15 

32.50 

83.85 

35J21 

36.56 

65.00 

28.13 

29.53 

30.94 

32.34 

83.75 

35.16 

86.56 

37.97 

67.50 

if 

29.17 

30.63 

32.08 

83.54 

35.00 

36.46 

37.92 

39.38 

70..00 

HI 

30.21 

31.72 

33.23 

34.74 

36.25 

3776 

39.27 

40.78 

72.50 

31.25 

32.81 

34.38 

35.94 

37.50 

39.06 

40.63 

42.19 

76.00 

*tt 

32.29 

83.91 

35.52 

37.14 

3875 

40.36 

41.98 

43.59 

77.50 

e 

33.33 

35.00  36.67  j  38.83  j  40.00 

41.67 

43.33 

45.00 

80.00 

WEIGHTS    OF   FLAT    ROLLED  IRON  PER 
LINEAL  FOOT. 

(CONTINUED.) 


Thickness 
ID  laches. 

1" 

7K" 

7*» 

7%<< 

, 

U>4 

b>2 

u;4 

As 

1.46 

1.51 

1.56 

1.61 

167 

1.72 

1.77 

1.82 

250 

1 

2.92 

302 

313 

3.23 

3.33 

3.44 

3.54 

365 

60C 

A 

4.38. 

4.53 

4.69 

4.84 

6.00 

516 

631 

6.47 

7.oO 

Y 

5.83 

6.04 

6.25 

6.46 

6.67 

688 

708 

7.29 

10.00 

IV 

7.29 

7.55 

7.81 

8.07 

8.33 

8.59 

8.85 

9.11 

12.50 

8.75 

906 

9.38 

9.69 

10.00 

10.31 

1063 

10.94 

1500 

ll 

10.21 

10.67 

10.94 

11.30 

11.67 

12.03 

12.40 

1276 

1750 

1167 

12.08 

12.50 

12.92 

13.33 

1375 

1417 

1458 

2000 

I\ 

1313 

1359 

14.06 

14.53 

1500 

1547 

1594 

16.41 

2250 

1 

14.58 

1510    15.63 

16.15 

1667 

1719 

1771 

18.23 

2500 

4 

16.04 

16.61 

1719 

1776 

18.33 

1891 

1948 

20.05 

27.50 

17.60 

1813 

1875 

1938 

2000 

20.63 

21.25 

21.88 

30.00 

H 

1896 

1964   2031 

2099 

2167 

22.34 

23.02 

23.70 

3250 

1 

2042 

21  15   21  88  22.60 

23.33 

24.06 

24.79 

2552 

35.00 

H 

2188 
2333 

22.66 
2417 

23.44 
25.00 

24.22 
25.83 

25.00 
26.67 

25.78 
27.50 

26.56  27.34 
28.3312917 

37.50 
4000 

,r 

2479 

2568 

26.56 

27.45 

28.33 

29.22 

30.10 

3099 

4250 

I  | 

26.25 

2719 

28.13 

29.06 

30.00 

30.94 

3188 

32.81 

45.00 

J    8 

27.71 

28.70 

29.69 

30.68 

81.67 

32.66 

33.65 

3464 

47.50 

1    1 

29.17 

30.21 

31.25 

32.29 

33.38 

34.38 

3542 

36.4C 

6000 

irV" 

30.62 

3172 

32.81 

33.91 

35.00 

36.09 

3719 

38.28 

68.50 

If* 

32.08 

33.23 

34,38 

35.52 

36.67 

37.81 

38.96 

4010 

55.00 

4 

33.54 

34.74 

35.94 

37.14 

38.33 

39.53 

4073 

4193 

57.50 

35.00 

36.25 

37.50 

38.75 

40.00 

41.25 

42.50 

43.75 

60.00 

IT'S 

36.46 

3776 

39.06 

40.36 

41.67 

42.97 

44.27 

45.57 

6250 

l| 

3792 

39.27 

40.63 

41.98 

43.33 

44.69 

46.04 

47.40 

6500 

Ifl 

39.38 

40.78 

42.19 

43.59 

45.00 

4641 

47.81 

49.22 

67.50 

'40.33 

42.29 

43.75 

45.21 

46.67 

48.13 

49.58 

51.04 

70.00 

HI 

42.29 

43.80 

45.31 

46.82 

48.33 

49.84 

51.35 

52.86 

>^50 

H 

43.75 

45.31 

46.88 

48.44 

50.00 

51  56 

53.13 

54.69 

75^00 

HI  - 

45.21 

46.82 

48.44 

50.05 

51.67 

53.28  [  54.90 

56.51 

77.50 

& 

46.67 

48.33 

50.00  1  51.67  j  53.33 

55.00  56.67  1  58.33 

80.00 

WEIGHTS    OF    FLAT    ROLLED  IRON   PER 
LINEAL  FOOT. 

(CONTINUED.) 


inlMfra. 

9" 

9tf< 

9V 

9*" 

10" 

UH» 

UH" 

10|" 

12" 

A 

1.88 

1.93 

1.98 

2.03 

2.08 

2.14 

2.19 

254 

2.50 

i 

S.75 

3.85 

8.96 

4.06 

4.17 

4.27 

4.38 

4.48 

6.00 

«* 

6.63 

6.78 

6.94 

6.09 

6.25 

6.41 

6.56 

6.72 

7.50 

1 

7.60 

7.71 

7.92 

8.13 

8.33 

8.54 

8.75 

8.96 

10.00 

A 

0.38 

9.64 

9.90 

10.16 

10.42 

10.68 

10.94 

1150 

12.50 

r*t 

1156 

11.56 

11.88 

12.19 

12.60 

12.81 

13.13 

13.44 

15.00 

A 

13.13 

13.49 

13.86 

1452 

14.68 

14.95 

15.31 

15.68^ 

-17.50 

16.00 

15.42 

15.83 

1655 

16.67 

17.08 

17.50 

17.92 

20.00 

•A 

16.88 

17.34 

17.81 

1858 

18.75 

1952 

19.69 

20.16 

22.50 

18.75 

19.27 

19.79 

20.31 

20.83 

21.35 

21.88 

22.40 

26.00 

'i* 

20.63 

2150 

21.77 

22.34 

22.92 

23.49 

24.06 

24.64 

27.60 

i 

22.60 

23.13 

23.75 

24.38 

25.00 

25.62 

2655 

26.88 

30.08  1 

if 

24.38 

25.05 

25.73 

26.41 

27.08 

27.76 

28.44 

29.fl 

32.50 

i 

2655' 

26.98 

27.71 

28.44 

29.17 

29.90 

30.63 

31.36 

35.00 

ft 

28.1ft 

28.91 

29.69 

80.47 

31.25 

32.03 

32.81 

33.59 

37.50 

\v 

30.00 

30.83 

31.67 

32.60 

33.33 

34.17 

35.00 

35.83 

40.00 

31.88 

82.76 

33.65 

34.53 

35.42 

36.30 

37.19 

38.07 

42.50 

11 

33.75 
35.63 

34.69 
36.61 

35.63 
37.60 

36.56 
38.59 

87.50 
89.68 

88.44 

40.57 

39.38 
41.56 

40.31 
42.55 

45.00 
47.50 

87.50 

88.54 

39.58 

40.63 

41.67 

42.71 

43.75 

44.79 

60.00 

1    • 

39.38 

40.47 

41.56 

42.66 

43.75 

44.84 

45.94 

47.03 

62.50 

11 

41.25 

42.40 

43.54 

44.69 

45.83 

46.98 

48.13 

4957 

65.00 

fi 

43.13 

44.32 

45.52 

46.72 

47.92 

49.11 

60.31 

51.51 

57,50 

M 

45.00 

4655 

47.60 

48.75 

60.00 

6155 

52.60 

53.75 

60.00 

a  A 

46.88 

48.18 

49.48 

50.78 

62.08 

53.39 

54.69 

55.99 

62.50 

if 

48.75 

60.10 

51.46 

62.81 

54.17 

55.52 

66.88 

5853 

65.00 

50.63 

52.03 

53.44 

64.84 

5655 

57.66 

59.06 

60.47 

€7.50 

i}** 

52.50 

53.96 

65.42 

56.88 

58.33 

59.79 

6155 

62.71 

70.00 

4H 

54.38 

65.89 

57.40 

58.91 

60.42 

61.93 

63.44 

64.95 

72.50 

1  1 

6655 

67.81 

59.38 

60.94 

62.50 

64.06 

65.63 

67.19 

75.CO 

Ul 

58.13 

59.74 

C1.35 

62.97 

64.58 

6650 

67.81 

69.43 

77.50 

2 

60.00 

61.67 

63.33 

65.00 

66.67. 

68.33. 

70.00 

71.G7 

80.00 

WEIGHTS    OF    FLAT    ROLLED   IRON  PER 
LINEAL  FOOT. 

(CONTINUED.) 


Tinckiees 
n  f  jc'hcs. 

m 

1H" 

11  r 

III" 

12" 

2i" 

12*" 

122" 

T: 

2.29 

2.34 

2.40 

2.45 

2.50 

2.55 

2.60 

2.66 

| 

4.58 

4.69 

4.79 

490 

5.00 

5.10 

5.21 

5.31 

J9 

6.88 

7.03 

7.19 

7.34 

7.50 

7.66 

7.81 

7.97 

i 

9.17 

9.38 

9.58 

9.79. 

10.00 

10.21 

10.42 

10.63 

j 

11.46 

11.72 

11.98 

12.24 

12.50 

12.76 

13.02 

13.28 

i 

3 

13.75 

14.03 

14.38 

14.69 

15.00 

15.31 

15.63 

15.94 

A 

10.04 

16.41 

16.77 

17.14 

17.50 

17.86 

18.23 

18.59 

1  0 

18.33 

18.75 

19.17 

19.58 

20.00 

20.42 

20.83 

2155 

T95 

2063 

21.09 

21.56 

22.03 

22.50 

22.97 

23.44 

23.91 

| 

22.92 

23.44 

23.96 

24.48 

25.00 

25.52 

26.04 

26.56 

U 

25.21 

25.78 

26.35 

26.93 

27.50 

28.07 

28.65 

2952 

V  , 

27.50 

28.13 

28.75 

29.38 

30.00 

30.63 

31.25 

31.88 

9 

41 

2979 

30.47 

31.15 

31.82 

32.50 

33.18 

33.85 

34.53 

f 

32.08 

32.81 

33.54 

34.27 

35.00 

35.73 

36.46 

37.19 

H 

34.38 

35.16 

35.94 

36.72 

37.50 

38.28 

39.06 

39.84 

38.67 

37.50 

38.33 

39.17 

40.00 

40.83 

4167 

42.50 

1-rV 

38.96 

39.84 

40.73 

41.61 

42.50 

43.39 

4457 

45.16 

(I? 

41.25 

42.19 

43.13 

44.06 

45.00 

45.94 

46.88 

47.81 

4 

43.54 

44.53 

45.52 

46.51 

47.50 

48.49 

49.48 

50.47 

1? 

45.83 

46.88 

47.92 

48.96 

50.00 

51.04 

52.08 

63.13 

t& 

48.13 

4952 

50.31 

51.41 

52.50 

53.59 

54.69 

65.78 

if 

50.42 

51.58 

52.71 

53.85 

55.00 

56.15 

5759 

68.44 

i.A 

52.71 

53.91 

55.10 

56.30 

57.50 

58.70 

59.90 

61.09 

IT 

55.00 

56.25 

5750 

58.75 

60.00 

61.25 

62.50 

63.75 

IT'* 

5759 

68.59 

59.90 

6150 

62.60 

63:80 

65.10 

&S.41 

H 

59.58 

60.94 

6259 

63.65 

65.00 

66.35 

67.71 

69.08 

JH 

61.88 

63.28 

64.69 

66.09 

67.50 

68.9 

70.31 

71.72 

i? 

64.17 

65.63 

67.08 

68.54 

70.00 

71.46 

72.92 

74.38 

Ht 

66.46 

67.97 

69.48 

70.99 

72.50 

74.0 

75.52 

77.03 

if 

68.75 

70.31 

7188 

73.44 

75.00 

76.56 

78.13 

79.6? 

w 

71.04 

72.66 

7487 

75.89 

7/.50 

79.1 

80.73 

82.34 

e  - 

73.33 

75.00 

76.67 

78.33 

80.00 

81.67 

83.33 

85.00 

1 

204 


Weight    of    Rivets,    and    Round    Headed    Bolts 
Without  Nuts,  Per  100. 

Length  from  under  head.     One  cubic  foot  weighing  480  Ibs. 


rngii. 
iches. 

•K" 
Dia. 

K 

%" 
Dia. 

DUL 

%" 
Dia. 

1" 
Dia. 

Dia. 

Dia. 

Vi 

5.4 

12.6 

21.5 

28.7 

43.1 

65.3 

91.5 

123. 

\% 

6.2 

13.9 

23.7 

318 

47.3 

70.7 

98.4 

133. 

1% 

6.9 

153 

25.8 

34.9 

51.4 

76.2 

105. 

142. 

2 

7.7 

16.6 

27.9 

87.9 

55.6 

81.6 

112. 

150. 

% 

8.5 

18.0 

30.0 

41.0 

59.8 

87.1 

119. 

159. 

2M 

9.2 

19.4 

32.2 

441 

63.0 

925 

126. 

167. 

2% 

10.0 

20.7 

34.3 

47.1 

68.1 

98.0 

133. 

176. 

U 

10.8 

22.1 

36.4 

50.2 

72.3 

103. 

140. 

184 

'* 

3^ 

11.5 

23.5 

88.6 

533 

765 

109 

147. 

193. 

8)£ 

12.3 

24.8 

407 

564 

807 

114. 

154. 

201. 

3% 

13.1 

26.2 

428 

594 

84.8  i  120. 

161. 

210. 

4 

13.8 

27.5 

45.0 

62.5 

800 

125. 

167. 

218. 

14.6 

28.9 

47.1 

65.6 

932 

131. 

174 

227. 

4}£ 

15.4 

30.3 

49.2 

68.6 

974 

136. 

181. 

236. 

43/ 

16.2 

81.6 

51.4 

717 

102 

142. 

188. 

244. 

6  ^ 

16.9 

33.0 

53.5 

74.8 

106. 

147. 

195. 

253. 

% 

17.7 

34.4 

556 

77.8 

110. 

153. 

202. 

261. 

5^ 

18.4 

85.7 

57.7 

80.9 

114. 

158. 

209. 

270 

65.4 

19.2 

37.1 

59.9 

'  84  0 

118 

163. 

216. 

278. 

6 

20.0 

38.5 

62.0 

87.0 

122. 

169 

223. 

287. 

6M 

21.5 

41.2 

66.3 

93.2 

131 

180* 

236. 

304  ' 

7 

230 

43.9 

70.5 

993 

139. 

191. 

250 

821. 

7K 

24.6 

46.6 

74.8 

106. 

147. 

202.  * 

264. 

888. 

8 

26.1 

49.4 

79.0 

112. 

156. 

213. 

278. 

855. 

/ 

4 

8^£ 

27.6 

52.1 

83.3 

118. 

164. 

223 

292     i  37f, 

9 

292 

54.8 

876 

124. 

173 

234. 

30C 

389. 

9K 

80.7 

67.6 

91.8 

130. 

18! 

245. 

319. 

406. 

10 

32.2 

60.3 

96.1 

136. 

189. 

256. 

333. 

423. 

10>£ 

83.8 

63.0 

101. 

142. 

198 

267. 

347. 

440/ 

11 

35.3 

65.7 

105. 

148. 

206. 

278. 

361. 

457. 

UK 

86.3 

685 

149. 

155. 

214. 

289 

375. 

474. 

1?c* 

38.4 

71.2 

113. 

161. 

223.^ 

300. 

388. 

491. 

<* 

leads. 

1.8 

5.7 

10.9 

13.4 

22.2 

88.0 

57.0 

205 

WEIGHT  OP  CAST  IRON  PER  LINEAL  FOOT. —Example:  What  Is 
weight  of  a  cast  iron  plate  2"  x  14"  x  one  foot  long?  Ans. — The 
thickness  multiplied  by  width  equals  28"  of  sectional  area. 

In  the  sixth  column,  we  find  that  87^  Ibs.  is  the  weight  of  a  piece 
with  a  sectional  area  of  28"  and  one  foot  long. 


Area! 

Area     T  Hfl 
Inches.;     Lb8' 

Area 

Inches 

Lbs. 

Area'    T  h_ 
Inches.     Lb9' 

Area 
Inches 

Lbs. 

1 

i 

1 

If 

.20 

6 

18.75 

21  V 

67.19 

48 

194.38 

69 

215.63 

fc 

.39 

6'4 

19.53 

22 

68.75 

43$  135.94 

70 

218.75 

•j\ 

.69 

6$ 

20.31 

22V 

70.31 

44     137.5 

71 

221.88 

v» 

.78 

6* 

21.09 

23 

71.88 

4  4  $[1*9.04 

72 

225.0 

I5? 

.98 

7 

1  21.88 

28V 

73.44 

45 

140.63 

73 

228.13 

2£ 

1.17 

71'4 

'  22.66 

24 

75.00 

45$ 

142.19 

74 

231.25 

A 

1.37 

iy 

23.44 

24?xJ 

76.56 

46 

148.76 

75 

234.38 

y* 

t.56 

7%. 

24.22 

26 

78.13 

46$  145.31 

76 

237.6 

A 

1.76 

8 

25.00 

25  y2 

79.69 

47    1146.87 

77 

240.63 

/M 

1.95 

8'4 

26.78 

26 

81.25 

47J4,;1  48.44 

78 

243.75 

H 

2.15 

26.56 

26^ 

82.81 

48      150.00 

79 

249.87 

3£ 

2.34 

83K 

27.34 

27 

84.38 

48$  151.56 

80 

250.00 

H 

2.54 

9 

28.13 

27$ 

85.94 

49 

163.12 

81 

253.12 

?'H 

2.78 

9V* 

28.91 

28 

87.5 

49$ 

154.69 

82 

256.25 

it 

2.93 

9!^ 

29.69 

28V£ 

89.06 

50 

156.25 

83 

259.38 

i 

3.125 

ft  if 

80.47 

29 

90.63 

60$ 

167.81 

84 

262.5 

IVa 

3.51 

10 

31.25 

29$ 

92.19 

51 

159.38 

85 

265.63 

IVi 

3.91 

lOVi 

82.03 

30 

93.75 

61V£ 

160.94 

86 

268.75 

1% 

4.30 

ioV£ 

32.81 

30$ 

95.31 

52 

162.5 

87 

271.88 

j  1$ 

4.69 

10?4 

33.59 

31 

96.87 

52$ 

164.06 

^88 

275.00 

5 

5.08 

11 

34.38 

31$ 

98.44 

53 

165.63 

89 

278.13 

1% 

6.47 

ni/i 

35.16 

32 

100.00 

63^ 

167.19 

90 

281.25 

>'•< 

5.86 

1  "  /2 

35.94 

32^ 

101.56 

54 

168.75 

91 

284.38 

6.25 

11% 

36.72 

33 

103.12 

W6 

170.31 

92 

287.6  J 

2Vs 

6.64 

12 

37.6 

33$ 

104.69 

65 

171.88 

93 

290.66 

2  1^ 

7.03 

ISVJj 

39.06 

34 

106.25 

W4 

173.44 

94 

293.76 

2% 

7.42 

13 

40.63 

84$ 

107.81 

56 

175.00 

95 

296.87 

2% 

7.81 

13$ 

42.19 

85 

109.38 

66$ 

176.56 

96 

300.00 

2% 

8.20 

14 

43.75 

35$ 

110.94 

57 

178.13 

97 

303.13 

8.59 

14$ 

45.31 

36 

112.5 

57^ 

179.69 

98 

306.25 

2% 

8.98 

15 

46.87 

36$ 

114.06 

58 

181.26 

99 

309.38 

8 

9.88 

15Va 

48.44 

37 

115.63 

68$ 

182.81 

100 

312.5 

3l/£ 

10.16 

16 

50.00 

87$ 

117.19 

59 

184.38 

101 

315.63 

4 

10.94 
11.72 
12  5 

17 

17V; 

51.56 
53.12 
54.69 

38 
88  J4 
39 

118.75 
120.31 
121.88 

59$ 
60 

61 

185.94 
187.5 
190.63 

102 
103 
104 
105 

318.75 
822.88 
325.00 
328.13 

4'/4 

13.28 

18        56.25 

39V£ 

123.44 

62 

193.75 

106 

331.25 

4$ 

14.06 

18H    57.81 

40 

25.00 

63 

196.87 

107 

334.88 

4* 

14.84 

19        69.88 

4  OX> 

26.56 

64 

200.00 

108 

837.5 

6  4ft 

lo.G3 

19$]    60.94 

41 

1-28.13 

65 

•203.125 

109 

340.63 

&^ 

16.41 

•JO        62.5 

41$  129.69 

C«      -206.25 

110 

343.75 

&$ 

17.  19 

20?  .j     64.06 

4'J     !  131.  2  5 

«         1-209.38 

111 

346.87 

112 

350.  OQ 

206 


ftlNEAR   EXPANSION   OP   SUBSTANCES 
BY   HEAT. 

To  find  the  increase  in  the  length  of  a  bar  of  any  material  due 
to  an  increase  of  temperature,  multiply  the  number  of  degrees 
of  increase  of  temperature  by  the  coefficient  for  100  degrees  and 
by  the  length  of  the  bar,  and  divide  by  100. 


NAME  OF  SUBSTANCE. 

Coefficient  for  100  c 
Fakrenheit. 

Coefficient  for  180° 
Fahrenheit,  or  IOC1 
CenUgradt 

Baywood,  (in  the  direction  of  the  J 

.00026 

TO 

.00046 

TO 

grain,  dry,)     »  • 

I 

.O0031 

00057 

Brass,  (cast,)    - 

. 

.O01O4 

00188 

"       (wire,) 

•f 

.00107 

.00193 

Brick,  (fire,)     . 

*, 

.0003 

.0005 

Cement,  (Roman,)  -             ^ 

/    ^ 

.0008 

.0014 

Copper,            -                  *  * 

•'. 

.0009 

.0017 

Deal,  (in  the  direction  of  the  grain,  J 

'.00024 

.00044 

dry,)      - 

Glass,  (English  flint,)  -    v   * 

s. 

.00045 

.00081 

"      (French  white  lead,) 

T'     ^ 

.00048 

.00087 

Gold,     .         -         .    v  -U  > 

-."*  ^  • 

.0008 

.0015 

Granite,  (average,)   •  -  *       > 

.00047 

.OOO85 

Iron,  (cast,)    -         •   %^  •   J 

^ 

.0006 

.0011 

"     (soft  forged,)  *    »     ••• 

.0007 

.0012 

"     (wire,)  -        :"VA^ 

"*   *      ' 

.0008 

.0014 

T      A                                 ""* 

0016 

OO9ft 

Marble,  (Carrara,)  -     x  *•    ^ 

V 

.00036 

TO 

.0006 

.00065 

to 
.0011 

Mercury,     -x        •      ,'*?.* 

^^ 

.0033 

.0060 

Platinum,    -   *v        •       '  • 

'. 

.0005 

.0009 

f 

.0005 

.0009 

Sandstone,  •         «         -         « 

TO 

TO 

1 

.0007 

.0012 

Silver,          •  ,  <•    ,^ 

Jf 

.0011 

.002 

Slate,  (Wales,)  .'fC;  . 

.0006 

.001 

Water,    (varies  considerably 
the  temperature,) 

with  ] 

.0086       ', 

.O155 

207 
Weight  of  Bolts  per  100,  Including  Nuts. 


1 

5 

I 

2 

DIAMETER. 

i 

A  ' 

« 

r7* 

1 

*'» 

1 

I 

•1 

4. 

4.36 
4.75 

7. 
7.60 

8. 

10.60 
11.25 
12. 

1520 
16.30 
17.40 

22.50 
23.82 
26.16 

39.60 
41.62 
48.75 

69. 

.  ...... 

*i 

6.15 

8.50 

12.75 

18.60 

26.47 

45.88 

72. 

.....'.-. 

*4 

6.60 

9. 

13.60 

19.60 

27.80 

48.' 

75. 

116.60 

1 

2J 

6.75 

9.60 

14.25 

20.70 

29.12 

60.12 

78. 

121.75 

i* 

«.*5 

10. 

16. 

31.80 

8Q.45 

52,25 

81. 

126. 

*i 

*7. 

11. 

16.50 

24. 

33.10 

56.50 

87. 

134.85 

7.76 

12. 

•9,f 

26.20 

36.76 

60  75 

93.10 

142.60 

207 

4* 

8.60 

13. 

19.60 

28.40 

38.40 

66. 

99.0^ 

151. 

219 

6 

9.26 

14. 

21. 

80.60 

41.06 

69.26 

105.20 

169.66 

22t 

6i 

10. 

16. 

22.60 

32.80 

43.70 

73.50 

111.26 

168.^ 

240 

](•  .5 

16. 

24. 

35. 

46.35 

77.75 

117.30 

176.60 

251 

J; 

25.60 

27. 
28.60 

87.20 
39.40 
41.60 

49. 
51.65 
54.30 

82. 
86.25 
90.60 

128.35 
129.40 
135. 

185. 
198.65 
202. 

261 
27S 

284 

8 

80. 

48.80 

59.60 

94.75 

141.50 

210.70 

295 

10 
11 

46. 
48.20 
60.40 

64.90 
70.20 
75.50 

103.25 
111.75 

1  20.26 

153.60 
166  70 
177.80 

227.75 
244.80 
261.&6 

317 
839 
360 



../v. 

12 

..     ' 

..  *N  . 

52.60 

80  8Q 

128.75 

189.90 

278.90 

382 

13 

.'». 

8&10 

137  25 

202 

29595 

404 

14 

.    :  ... 

91.40 

115.75 

214.10 

3  1  3.' 

426 

15 
16 
17 
18 
19 

'    i    « 

Y"  
....         ....... 

_: 

96  70 
102. 

154  25 
162.  70 

226.20 
238.30 
•250.40 
262.60 
274.70 

33005 
347.10 
364.15 
381  20 

398.25 

44» 
470 
492 
614 
636 

........ 

i;     1 

107.30 
1  12.60 
117.  HO 

179.50 

188. 

•  r._ 

••  '•    1  

80 

>    '               1   .    .    • 

•  •••  j   

188.20 

200  50 

286.80 

415.30 

55J 

208 
TENSILE  STRENGTH  OF  COMMON  WOODS. 

The  strongest  wood  which  grows  within  the  confines  of  the 
United  States  is  that  known  as  "nutmeg"  hickory,  which, 
grows  in  the  valley  of  the  lower  Arkansas  river.  The  most 
elastic  is  tamarack.  The  wood  with  the  least  elasticity  and 
lowest  specific  gravity  is  the  Picus  aurea.  The  wood  having 
the  highest  specific  gravity  is  the  blue  wood  of  Texas  and 
Mexico. 

The  heaviest  of  foreign  woods  are  the  pomegranate  and 
the  lignum  vitas;  the  lightest  is  cork,  which,  however,  is  a 
bark,  not  solid  wood.  The  tensile  strength  of  the  best  known 
woods  is  set  forth  in  the  following  schedule: 


WOOD.  POUNDS. 

Ash 14,000 

B3ech 11,500 

Cedar 11.400 

Chestnut 10.500 

Cypress 6,000 

Elm 13.400 

Fir 12.000 

Maple 10.500 

White  Oak 11.500 

Pear 9,800 

Pitch  Pine 12,000 


WOOD.  POUNDS. 

Larch 9,500 

Poplar , ..    7,000 

Spruce 10,290 

Teak 14,000 

Walnut 7,800 

Lance 23.000 

Locust 20,500 

Mahogany 21.000 

Willow 13,000 

Lignum  Vitse 11,800 


Pour  hundred  and  thirteen  different  species  of  trees  grow 
in  the  various  states  and  territories,  and  of  this  number  10, 
when  perfectly  seasonable,  will  sink  in  water. 

TEMPEEING  STEEL  PUNCHES. 

Heat  your  steel  to  cherry-red,  dress  out  the  punch,  cut 
off  the  point  the  size  of  a  horseshoe  nail,  then  heat  to  a 
cherry-red,  immerse  it  a  half  inch  perpendicularly  in  the 
water,  then  take  it  out  and  stand  it  up  perpendicular,  clean 
the  end  with  a  piece  of  grinding  stone.  When  you  see  the 
first  blue  pass  over  the  point,  dip  it  in  the  water  the  same 
depth  as  before.  Clean  it  again  with  the  stone,  and  on  the 
appearance  of  the  blue  again,  cool  it  off.  The  second  blue 
is  to  make  the  punch  tough.  The  reason  for  keeping  the 
punch  perpendicular  is  to  allow  the  atmosphere  and  the 
water  to  cool  all  sides  equally,  and  to  have  it  cool  straight 
and  true. 

HOW  TO  MAKE  TRACING  PAPER. 
Take  some  good  thin  printing  paper,  and  brush  it  over  on 
one  side  with  a  solution  consisting  of  one  part,  by  measure, 
of  castor  oil  in  two  parts  of  meth.  spjrit ;  blot  off  and  hang  up 
to  dry.  You  can  trace  by  pencil  or  ink  on  this.  I  have  tried 
it  and  done  it. 


209 

IN  THE   SHOP  — TURNING  A  BALL. 
To  make  a  ball  as  nearly  perfect  as  a  billiard  ball  is  made, 
is  not  a  piece  of  work  that  often  falls  to  the  lot  of  the 
machinist    or   pattern-maker  ;    but   occasionally   arises   the 
necessity  for  such  work. 

In  pumping  where  chips,  sawdust,  or  dust  is  very  liable  to 
lodge  on  the  seat  under  the  valve,  ball  valves  are  sometimes 
used,  because  their  rolling  motion  has  a  tendency  to  remove 
the  obstruction,  and  let  the  valve  seat  fairly  again.  Some  of 
the  old-style  locomotive  pumps  had  ball  valves ;  and,  in 
tannery  work,  when  small  pieces  of  bark  are  liable  to  be  ir 
the  liquid,  ball  valves  can  be  used  to  advantage. 

I  have  some  such  valves,  four  or  five  inches  in  diameter, 
for  tanner's  use.  They  were  of  brass,  cast  hollow,  with  the 
core  holes  in  the  shell  plugged. 

I  have  seen  some  costly  machines  which  were  made  for  the 
purpose  of  turning  balls;  but  I  have  never  seen  any  better 
work  done  by  them  than  can  be  done  in  a  common  lathe. 

To  make  the  pattern  of  a  ball,  first  turn  the  piece  on 
centers,  using  the  calipers  to  get  it  approximately  near  the 
shape,  and  then  cut  off  the  centers.  Next  make  a  chuck- 
block  of  hardwood,  A,  as  shown  in  the  cut,  Fig.  I.  Make 
a  cup. in  the  block  to  receive  a  small  section  of  the  ball,  as 
also  indicated.  A  blunt,  wood  center  is  sometimes  used 
instead  of  the  steel  center  with  a  concave  piece  of  copper,  as 
represented  in  cut.  Either  way  will  do  for  making  the 
pattern.  Put  the  work  in  the  chuck  so  as  to  take  the  first  cut 
around  it  in  the  direction  of  its  former  centers,  or  axis. 

Cut  lightly,  and  do  not  try 
to  make  a  wide  space — let  it 
be  only  a  narrow  ribbon  or 
turning  —  but  get  it  round 
in  the  direction  of  present 
revolution  ;  then  change  the 
chuck  so  as  to  make  another 
ribbon  at  right  angles  to  the 
first,  the  first  tool  marks 
being  the  guide  for  the  depth 
of  the  second  cutting.  Next 
change  the  work  so  as  to  get 
a  ribbon  between  the  other  cuts,  and  continuing  this  process  of 
changing  and  turning  over  the  whole  surface,  thus  making  the 
axis  of  the  pattern  oY  equal  length  in  all  directions,  and  then 
the  pattern  will  be  round — it  will  be  a  ball.  At  first  it  might 
seern  as  if  some  laying  off  were  needed  to  get  {he  "  ribbons," 


as  I  have  called  them,  at  right  angles  to  each  other,  but  there 
is  no  need  of  that ;  by  the  eye  is  enough. 

When  the  machinist  comes  to  finish  up  the  casting,  he 
can  bolt  the  chuck-block  to  his  face  plate,  and  use  his  steel 
center  and  a  concave  piece  of  copper  as  represented  in  the 
cut.  He  will  have  to  use  a  hand  tool,  or  a  scraper,  after 
getting  under  the  scale. 

If  the  ball  becomes  too  small  for  the  cup  in  the  block,  it 
is  an  easy  matter  to  make  a  new  fit  by  cutting  deeper  into  the 
chuck -block. 

THE    ACTION    OF    SEA-WATKR    ON    CAST-IRON 

PILES. 

Indiana  Engineering  notes  the  results  of  some  observa- 
tions made  by  the  chief  engineer  of  the  B.  B.  and  C.  I. 
Railway  on  the  cast-iron  piles  forming  the  piers  of  the  South 
Bassien  bridge.  The  piles  were  put  down  in  1862.  Two 
were  found  almost  as  fresh  in  appearance  as  when  sunk,  and 
showed  no  corrosions  in  specimens  cut  from  the  metal.  The 
deepest  corrosion  found  on  any  pile  was  ^  inch ;  and  this 
corrosion  was  the  greatest  near  low-water  mark.  The  pile 
bolts  were  all  in  excellent  condition.  All  of  these  piles  have 
been  exposed  to  the  action  of  sea-water  for  about  twenty- 
five  years,  and  the  examination  was  made  to  set  aside  a  current 
suspicion  that  they  were  deteriorating  under  the  action  of  the 
water. 

JAPANESE  WATER  PIPES. 

The  water  supply  of  Tokio,  Japan,  is  by  the  wooden  water 
pipe  system,  which  has  been  in  existence  over  two  hundred 
years,  furnishing  at  present  a  daily  supply  of  from  twenty-five 
to  thirty  million  gallons.  There  are  several  types  of  water 
pipes  in  use,  the  principal  class  being  built  up  with  plank, 
square,  and  secured  together  by  frames  surrounding  them  at 
close  intervals.  The  pipes,  less  than  six  inch,  consist  of  bored 
logs,  and  somewhat  larger  ones  are  made  by  placing  a  cap  on 
the  top  of  a  log  in  which  a  very  large  groove  has  been  cut. 
All  the  connections  are  made  by  chamfered  joints,  and  cracks 
are  calked  with  an  inner  fibrous  bark.  Square  boxes  are 
used  in  various  places  to  regulate  the  uniformity  of  the  flow 
of  the  water,  which  is  rather  rapid,  for  the  purpose  of  pre- 
venting aquatic  growth.  TI.c  water  is  not  delivered  to  the 
houses,  but  into  reservoirs  oa  the  sides  of  the  streets,  nearly 
1 5, ooo  in  number. 


THE  HEATING  POWER  OF  FUEL. 

The  heating  power  of  fuel  is  ascertained  by  the  foil,  »Ting 
process,  which  consists  in  burning  one  gramme  of  the  o  1  or 
fuel  in  a  small  platinum  crucible,  supported  on  the  bow  f>f  a 
tobacco  pipe,  and  covered  by  an  inverted  glass  test  4i  ,be, 
through  which  is  passed  a  stream  of  oxygen,  while  the  i  pie 
is  placed  under  water  in  a  glass  vessel.  The  oxygen  i  fed 
into  the  test  tube  by  a  movable  copper  tube,  which  ma^  ^e 
pushed  into  the  test  tube  so  as  to  come  immediately  over  tJiC. 
crucible.  The  coals  burn  away  in  a  few  minutes  with  very 
intense  heat,  and  the  hot  gases  escape  through  the  water,  the 
bubbles  being  broken  up  by  pissing  through  sheets  of  wire 
gauze  which  stretch  between  the  test  tube  and  the  walls  of 
the  vessel  containing  the  water  in  which  it  is  placed.  The 
temperature  of  the  water  is  taken  before  and  after  the 
experiment,  and,  from  the  figures  thus  obtained,  the  heating 
power  of  the  coal  is  calculated. 

THE  DEVELOPMENT  OF  ELECTRICITY. 

There  are  now  about  $6,000,000  invested  in  the  manufac- 
ture of  electric  motors  in  the  United  States,  and  this  large 
investment  has  nearly  all  been  made  within  the  last  three  or 
four  years.  It  represents  either  the  independent  invest- 
ment of  companies  engaged  in  the  exclusive  manufacture 
of  motors,  or  an  increase  in  the  capitalization  of  companies 
that  manufacture  electric  appl'ances,  and  find  the  construc- 
tion of  electric  motors  a  good  auxiliary  industry.  Some 
of  these  companies  employ  many  hundred  men,  some- 
times approaching  a  thousand,  and  they  turn  out  motors 
almost  innumerable  each  year.  These  motors  are  of  all  sizes, 
from  one-ha'f  horse  power,  for  driving  sewing  machines  and 
such  other  light  work,  up  to  several  hundred  horse  power  for 
heavy  work.  They  are  becoming  a  driving  force  in  almost 
every  industry,  and  can  be  utilized  in  localities  where  the  cost 
of  obtaining  fuel  would  almost  equal  their  open  ting  expenses. 
The  chief  secret  of  the  rapid  advance  of  this  new  mechanical 
agent  is  found  in  the  flexibility  of  its  resources.  Electricity  is 
not  the  generator  of  power,  but  only  the  agency  for  its  trans- 
mission and  distribution,  as  it  is  an  agent  for  the  transmission 
of  the  human  voice  over  the  telephone  wire.  Through  its 
resources,  power  can  be  distributed  to  any  point,  and  in 
quantities  to  suit  the  customer.  Steam,  water,  nir,  caloric,  or 
any  known  agency  for  generating  power,  is  either  stationary 
or' it  demands  stationary  appliances;  but  electricity  is  its 
messenger  boy,  its  "  Puck,"  who  will  consent  to  do  its  errands 


invisibly,  and  never  ask  a  clay  off  or  the  grant  of  liberty. 
Does  a  lady  want  an  infinitesimal  bit  of  electrical  energy  to 
relieve  her  boot  on  the  treadle  of  her  sewing  machine,  it  can 
be  delivered  in  her  room  through  an  iron  box  not  much  bigger 
than  her  reticule.  Is  the  restaurant  keeper  plagued  by  an 
invasion  of  flies  that  expel  all  but  the  most  hungry  and  least 
profitable  customers,  they  can  be  gently  \vafted  to  the  door 
by  a  multitude  of  revolving  fans,  and  turned  out  either  into 
the  bright  sunlight  or  the  refreshing  shower.  Everywhere, 
anywhere,  without  a  particle  of  dust,  offensive  odor  or  dis- 
agreeable noise,  the  electric  motor  can  be  set  to  work,  and, 
tvhile  it  will  bring  the  substance  of  the  thing  wanted,  it  will 
leave  behind  everything  that  can  give  offense.  The  electric 
motor  has  passed  its  experimental  stages,  and  the  day  seems 
to  be  rapidly  approaching  when  every  house  will  find  sorae- 
thing  for  it  to  do  in  lifting  burdens  from  floor  to  floor,  and 
performing  every  possible  labor  that  can  be  done  by  machinery. 
Manufacturers  have  not  yet  begun  to  construct  motors  orna« 
mented  with  gold  leaf,  mother  of  pearl,  and  precious  stones, 
to  rock  cradles  in  the  nurseries,  but  these  requirements  will 
come  in  time. 

CHEMICAL  OR    PHYSICAL   TESTS    FOR  STEEL. 

Captain  Jones,  of  the  Edgar  Thomson  Steel  Works, 
Pittsburg,  was  in  Edinburgh  at  the  meeting  of  the  Union  and 
Steel  Institute,  and,  when  invited  to  speak,  said  he  could  not 
let  what  Mr.  Clark  had  said  about  the  practice  of  punching 
steel  plates  in  America  pass  without  comment.  Punching 
steel  plates  was  a  relic  of  barbarism,  and  there  was  an  appro- 
priateness about  the  president's  suggestion,  to  "  punch  a  man 
who  punched  a  plate."  As  to  the  relative  cost  of  punching 
and  drilling,  he  had  long  since  made  up  his  mind  about  that, 
for  many  years  ago,  in  constructing  a  roof,  he  had  drilled  all 
the  holes  and  found  it  cheaper  than  punching.  With  regard 
to  the  use  of  steel  in  America,  they  found  boiler-makers, 
bridge-makers  and  many  others  using  it  largely.  They  had 
started  with  physical  tests,  not  chemical  analysis,  but  they 
had  come  to  the  conclusion  that  physical  tests  could  be  met, 
andl  yet  the  metal  not  be  what  it  should  be.  The  test  foi 
boiler  plates  at  the  Edgar  Thomson  Works  was  higher  than 
thai  demanded  for  the  boiler  plates  of  the  United  States 
cruiy»ts,  the  limit  for  phosphorus  being  .035,  and  manganese, 
.350  jier  cent,  He  had  seen  steel  made  in  America,  where 
the  heftt  had  been  blown  for  eight  minutes,  the  manganese 
being  put  in  cold,  and  he  was  of  opinion  that  the  reaction 
had  not  taVen place  up  to  the  time  of  sinking.  With  regard 


213 

to  steel  for  bridge  construction,  he  considered  that  not  more 
than  .065  per  cent,  of  phosphorus  should  be  present,  and  the 
manganese  should  be  kept  low,  as  that  was  the  great  oxidiz- 
ing agent.  He  would  like  to  see  these  conditions  enforced 
by  law.  In  conclusion  he  wished  to  impress  on  his  hearers 
the  necessity  for  judging  steel  by  chemical  tests  first,  and  let- 
ting the  physical  tests  be  subsidiary  to  them. 

SUGGESTIONS  TO  STEEL  WORKERS. 

Messrs.  Miller,  Metcalf  £  Parkin,  of  Pittsburgh,  have 
issued  a  pamphlet  on  this  subject.  They  draw  attention  to 
the  following  points : 

Annealing — There  is  nothing  gained  by  heating  n.  piece 
of  steel  hotter  than  a  bright  cherry-red  heat  ;  on  the  contrary, 
a  higher  heat  may  render  the  steel  harder  on  cooling  than 
would  be  the  case  with  the  heat  just  mentioned.  Besides 
this,  the  scale  formed  would  be  granular,  and  would  spoil  the 
tools  to  be  used  in  working  the  metal,  and  the  metal  itself 
Would  change  its  structure,  and  become  brittle. 

Steel  should  never  be  left  in  a  hot  furnace  over  night,  as 
the  metal  becomes  too  hot,  and  is  spoilt  for  after  treatment. 

Forge  Steel — The  difficulty  experienced  in  the  forge  fire  is 
usually  due  more  to  uneven  heat  than  to  a  high  temperature. 
If  heated  too  rapidly,  the  outside  of  the  bar  becomes  soft, 
while  the  inside  is  still  hard,  and  at  too  low  a  temperature  for 
treatment. 

In  some  cases  a  high  heat  is  more  desirable  to  save  heavy 
labor ;  but  in  every  case  where  a  fine  steel  is  to  be  used  for 
cutting  purposes,  it  must  be  borne  in  mind  that  every  heavy 
forging  refines  the  bars  as  they  slowly  cool,  and,  if  the  smith 
heats  such  refined  bars  until  they  are  soft,  he  raises  the  grain, 
makes  them  coarse,  and  he  cannot  get  them  fine  again,  unless 
he  has  a  very  heavy  steam  hammer  at  command,  and  knows 
how  to  use  it  well. 

When  the  steel  is  hot  through,  it  should  be  taken  from 
the  fire  immediately,  and  forged  as  quickly  as  possible. 
w  Soaking "  in  the  fire  causes  steel  to  become  "  dry "  and 
brittle,  and  does  it  very  great  injury. 

Temper — The  word  "  temper,"  as  used  by  the  steelmaker  t 
indicates  the  amount  of  carbon  in  steel ;  thus,  steel  of  high 
temper,  is  steel  containing  much  carbon  ;  steel  of  low  temper, 
is  steel  containing  little  carbon  ;  steel  of  medium  temper  is 
steel  containing  carbon  between  these  limits.  Between  the 
highest  and  the  lowest,  there  are  some  twenty  divisions,  each 
representing  a  definite  percentage  of  carbon. 

The  act  of  tempering  steel  is  the  act  of  giving  to  a  piece 


214 

of  Steel,  after  it  has  been  shaped,  the  hardness  necessary  for 
the  work  it  has  to  do.  This  is  done  by  first  hardening  the 
piece — generally  a  good  deal  harder  than  is  necessary  —  and 
then  toughening  it  by  slow  heating  and  gradual  softening  until 
it  is  just  right  for  work. 

A  piece  of  steel,  properly  tempered,  should  always  be 
finer  in  grain  than  the  bar  from  which  it  is  made.  If  it  is 
necessary,  in  order  to  make  the  piece  as  hard  as  is  required, 
to  heat  it  so  hot  that  after  being  hardened  it  will  be  as  coarse 
or  coarser  in  grain  than  the  bar,  then  the  steel  itself  is  of  too 
low  a  temper  for  the  desired  purpose.  In  a  case  of  this  kind, 
the  steelmaker  should  at  once  be  notified  of  the  fact,  and 
could  immediately  correct  the  trouble  by  furnishing  higher 
steel. 

Heating — There  are  three  distinct  stages  or  times  of 
heating : 

First,  for  forging  ;  second,  for  hardening  ;  third,  for 
tempering. 

The  first  requisite  for  a  good  heat  for  forging  is  a  clean 
fire,  and  plenty  of  fuel,  so  that  jets  of  hot  air  will  not  strike 
the  corners  of  the  piece  ;  next,  the  fire  should  be  regular,  and 
give  a  good  uniform  heat  to  the  whole  part  to  be  forged.  It 


should  be  keen  enough  to  heat  the  piece  as  rapidly  as  possible, 
and  allow  it  to  be  thoroughly  heated  through,  without  being 
so  fierce  as  to  overheat  the  corners.  Steel  should  not  bj  left 


in  fire  any  longer  than  is  necessary  to  heat  it  through  ;  and, 
on  the  other  hand,  it  is  necessary  that  it  should  be  hot  through 
to  prevent  surface  cracks,  which  are  caused  by  the  reduced 
cohesion  of  the  overheated  parts  which  overlie  the  colder 
central  portion  of  an  irregularly  heated  piece. 

By  observing  these  precautions,  a  piece  of  steel  may 
always  be  heated  safely  up  to  even  a  bright  yellow  heat  when 
there  is  much  forging  to  be  done  on  it,  and  at  this  heat  it  will 
weld  well.  The  best  and  most  economical  of  welding  fluxes 
is  clean,  crude  borax,  which  should  be  first  throughly  melted, 
and  then  ground  to  fine  powder.  Borax,  prepared,  in  this 
way,  will  not  froth  on  the  steel,  and  one-half  of  the  usual 
quantity  will  do  the  work  as  well  as  the  whole  quantity 
un  melted. 

After  the  steel  is  properly  heated,  it  should  be  forged  to 
shape  as  quickly  as  possible ;  and,  just  as  the  red  heat  is 
leaving  the  parts  intended  for  cutting  edges,  these  parts 
should  be  refined  by  rapid,  light  blows,  continued  until.the  red 
disappears. 

tror  the  second  stnge  of  heating,  for  hr.rdenin^;,  great 
care  should  be  used,  first,  to  protect. the  cutting  edges  and 


215 

working  parts  from  heating  more  rapidly  than  the  body  of 
the  piece  ;  next,  that  the  whole  part  to  be  hardened  he  heated 
uniformly  through  without  any  part  becoming  visibly  hotter 
than  the  other.  A  uniform  heat,  as  low  as  will  give  the 
required  hardness,  is  the  best  for  hardening.  For  every 
variation  of  heat  which  is  great  enough  to  be  seen,  there  will 
result  a  variation  in  grain,  which  may  be  seen  by  breaking 
the  piece  ;  and  for  every  variation  in  temperature,  a  crack  is 
likely  to  be  produced.  Many  a  costly  tool  is  ruined  by 
inattention  to  this  point.  The  effect  of  too  high  a  heat  is  to 
open  the  grain  —  to  make  the  steel  coarse.  The  effect  of  an 
irregular  heat  is  to  cause  irregular  grain,  irregular  strains  and 
cracks. 

As  soon  as  the  piece  is  properly  heated  for  hardening,  it 
should  be  promptly  and  thoroughly  quenched  in  plenty  of  the 
cooling  medium  —  water,  brine,  or  oil,  as  the  case  maybe. 
An  abundance  of  the  cooling  bath,  to  do  the  work  quickly 
and  uniformly  all  over,  is  very  necessary  to  good  and  safe 
work ;  and  to  harden  a  large  piece  safely,  a  running  stream 
should  be  used.  Much  uneven  hardening  is  caused  by  the  use 
of  too  small  baths. 

For  the  third  stage  of  heating,  to  temper,  the  first 
important  requisite  is  again  uniformity ;  the  next  is  time. 
The  more  slowly  a  piece  is  brought  down  to  its  temper,  the 
better  and  safer  is  the  operation.  When  expensive  tools, 
such  as  taps,  rose  cutters,  etc.,  are  to  be  made,  it  is  a  wise 
precaution,  and  one  easily  taken,  to  try  small  pieces  of  the 
steel  at  different  temperatures,  so  as  to  find,  out  how  low  a 
heat  will  give  the  necessary  hardness.  The  lowest  heat  is  the 
best  for  any  steel ;  the  test  costs  nothing,  takes  very  little 
time,  and  very  often  saves  considerable  loss. 

SUCCESSFUL     TESTS     OF     SHEFFIELD     STEEL 
ARMOR    PLATES. 

The  fourth  of  a  series  of  trials  of  steel  plates  took  place 
on  board  the  Nettle,  at  Portsmouth,  England,  last  week. 
The  plate,  which  was  manufactured  by  Messrs.  Vickers,  Sons 
&  Company,  Limited,  River  Don  Works,  Brightside,  Shef- 
field, was  of  the  dimensions  and  thickness  prescribed  for 
these  tests,  viz.,  8  feet  by  6,  and  1O)4  inches  thick.  It  was 
fired  at  by  a  six-inch  diameter  breech-loading  gun,  with  a 
charge  of  48  Tbs.  of  powder  and  100  Ibs.  shot.  The  first 
shot  was  a  Holtzer  hardened  steel  shot,  the  point  of  which 
penetrated  as  far  as  the  wood  backing,  and  was  driven  out 
again  by  the  elasticity  of  the  steel  with  such  force  that  the 


216 

shot  stuck  the  bulkhead  through  which  the  gun  was  fired 
Only  slight  cracks  were  made  round  the  hole  made  by  the 
projectile.  The  second  shot,  also  a  Holtzer,  did  not  pene- 
trate to  the  backing,  as  far  as  could  be  seen.  It  rebounded 
in  the  same  way  as  the  first  one,  and  caused  a  slight  crack 
at  the  top  end  of  the  plate.  The  third  and  fourth  Palliser, 
98  lb.  cast-iron  chilled  shot,  which  went  to  pieces  against 
the  plate,  only  causing  an  extension  of  the  crack  made  by 
the  second  shot  ;  and  the  fifth  shot,  another  Holtzer,  was 
also  sent  back  to  the  front,  after  making  a  slight  penetration 
in  the  wood  backing.  These  results  are  considered  as  very 
Satisfactory  by  those  who  witnessed  them,  the  target  having 
resisted  all  the  shots  fired  at  it,  and  looking  quite  able  to 
resist  still  further  trial.  The  shot  appeared  to  be  of  unusually 
good  steel ,  as  only  one  seemed  seriously  distorted  by  the 
work. 

WATCH  AND  LEARN. 

This  is  an  excellent  motto  for  every  young  man  to  adopt, 
and,  by  a  close  observance  of  it,  it  will  prove  of  great  value, 
even  after  he  becomes  grown  up  and  starts  out  in  business 
for  himself.  There  is  no  surer  way  of  gaining  knowledge 
than  by  a  careful  an  I  understanding  watchfulness  of  others 
in  the  sani^  Iiii3  of  business  as  yourself.  As  an  apprentice, 
you  cannot  expect  to  know  everything,  and  the  best  way  to 
gain  information  from  others  is  to  show  a  willingness  to 
learn  ;  then  they  will  take  an  interest  in  teaching.  But  if, 
as  is  too  often  the  case,  a  young  man,  after  he  lias  been  a  few 
months  in  a  place,  pretends  to  know  as  much,  and  sometimes 
more,  than  those  much  older  and  more  experienced  than  him- 
self, he  will  not  get  much  information  from  his  fellow  work- 
men ;  neither  will  he  retain  their  good  will  for  any  length  of 
time,  and  may  expect  to  have  all  manner  of  practical  jokes 
played  upon  him.  As  a  journeyman,  if  you  are  intelligent, 
you  will  very  often  have  occasion  to  believe  that  you  do  not 
know  it  all,  and,  in  fact,  the  longer  you  live  and  the  more 
you  learn,  the  more  you  will  find  that  there  is  to  be  learned. 
The  egotistical  and  loud  man  is  seldom  a  perfect  man,  and  is 
generally  very  far  from  being  as  near  perfection  as  he  would 
have  others  think  him.  The  person  who,  on  a  first  acquaint- 
ance, is  anxious  to  tell  you  what  he  knows,  and  is  very  free 
in  givingadvice  and  information  without  the  asking,  generally 
exhausts  the  supply  before  very  long.  He  who  is  willing  to 
listen  is  generally  the  one  whose  source  of  information  is 
"broader  and  of  a  more  durable,  valuable  and  substantial 
ki*?d  An  example  may  prove  the  idea  to  be  conveyed  more 


217 

clearly.  An  employer  was  in  want  of  a  good,  practical  and 
experienced  man  for  a  certain  class  of  work.  A  young 
man  applied  for  the  position,  who  was  very  certain  that  he 
"  knew  all  about  the  machine,"  and  he  was  engaged.  It  was 
not  long  before  every  man  in  the  shop  knew  all  that  he  did, 
and  one  very  valuable  thing  that  he  did  not,  and  that  was 
that  he  did  not  know  all  that  he  pretended  to.  His  manner 
and  braggadacio  very  soon  got  most  of  the  men  down  on 
him.  They  were  not  disappointed.  The  new  machine 
arrived,  and  was  set  up  ready  for  operation.  The  young 
man  was  given  a  job  to  be  worked  ofif,  and  began  operation? 
with  that  self-conscious  air  of  superiority  that  is  generally 
apparent  in  characters  of  this  description.  One  whole  day 
he  worked  at  the  job,  and  it  was  not  then  in  a  condition  to  be 
run.  Not  only  that,  but  he  had  shown  to  the  men,  who,  of 
course,  were  secretly  watching  him,  that  he  knew  practically 
nothing  of  the  machine.  Then  he  begoi  to  lay  the  blame 
for  the  trouble  upon  others,  and  asked  assistance  and 
"  points  "  from  some  of  the  other  workmen.  This  of  course 
he  did  not  get,  and  finally  another  man  was  put  on  the  job, 
and  he  was  discharged  amid  the  taunts  and  ridicule  of  the 
others.  If  the  young  man  had  shown  good  sense  when  he 
first  came  into  the  shop  ;  not  been  quite  so  free  to  tell  all  he 
knew,  and  had  shown  a  willingness  to  learn,  there  was  not  a 
man  in  the  place  that  would  not  have  gladly  assisted  him,  and 
he  might  have  remained  in  a  good  position.  It  sometimes 
pays  to  be  ignorant,  at  least  a  little  modesty  is  a  good  thing 
to  take  with  you  on  going  to  a  new  place.  If  you  know  more 
than  you  pretend,  it  will  soon  be  found  out,  and  you  will  be 
the  gainer;  but,  if  you  fail  to  make  good  your  pretensions,  not 
only  your  employer  but  all  your  fellow  workmen  will  be 
"down  on  you,"  and  things  will  be  correspondingly 
unpleasant. 

DEOXIDIZED   COPPER. 

The  advantages  to  be  obtained  by  the  use  of  copper  as 
nearly  chemically  pure  as  possible,  are  generally  admitted, 
whether  the  metal  be  used  as  copper,  or  in  the  form  of  brass, 
bronze,  or  the  many  other  alloys  into  which  it  enters.  The 
Deoxidized  Metal  Company,  of  Bridgeport,  Conn.,  claims 
that  the  desired  result  is  secured  by  the  process  which  is  used 
in  its  works.  The  castings  of  brass,  bronze,  etc. ,  made  under 
this  process,  are  most  excellent,  while  the  sheet  copper  and 
brass,  and  the  wire  made,  when  submitted  to  careful  tests, 
show  an  unusually  high  degree  of  strength,  copper  wire  hav- 
ing been  tested  up  to  70,000  Ibs.  per  square  inch,  tensile 


218 

strength.  The  deoxidized  metal  also  possesses  the  property 
of  great  resistance  to  acids,  so  that  it  can  be  used  for  many 
purposes  where  ordinary  metal  is  soon  destroyed  by  the 
chemical  action.  Journal-bearings  made  from  this  .metal 
have  also  been  tested  with  very  favorable  results,  while  for 
bells  it  is  claimed  that  the  tone  and  quality  is  much  superior 
to  ordinary  brass. 

MAKING  JAPANNED  LEATHER 

Japanned  leather,  generally  called  patent  leather,  was  first 
made  in  America.  A  smooth,  glazed  surface  is  first  given  to 
calfskin  in  France.  The  leather  is  curried  expressly  for  this 
purpose,  and  parcicular  care  is  taken  to  keep  as  free  as  pos- 
sible from  grease;  the  skins  are  then  tacked  on  frames  and 
coated  with  a  composition  of  linseed  oil  and  umber— in  the 
proportion  of  18  gallons  of  oil  to  5  of  umber— boiled  until 
nearly  solid,  and  then  mixed  with  spirits  of  turpentine  to  its 
proper  consistency.  Lampblack  is  also  added  when  the  com- 
position is  applied,  in  order  to  give  color  and  body.  From 
three  to  four  coats  are  necessary  to  form  a  substance  to  re- 
ceive the  varnish.  They  are  laid  on  with  a  knife  or  scraper. 
To  render  the  goods  soft  and  pliant  each  coat  must  be  very 
light  and  thoroughly  dried  after  each  application. 

A  thin  coat  is  afterward  applied  of  the  same  composition, 
of  proper  consistency,  to  be  put  on  with  a  brush,  and  with 
sufficient  lampblack  boiled  in  it  to  make  a  perfect  black. 
When  thoroughly  dry  it  is  cut  down  with  a  scraper  aaving 
turned  edges.  It  is  then  ready  to  varnish.  The  principal 
varnish  used  is  made  of  linseed  oil  and  Russian  blue  boiled 
to  the  thickness  of  printers'  ink.  It  is  reduced  with  spirits 
of  turpentine  to  a  suitable  consistency  to  work  with  a  brush 
and  then  applied  in  two  or  three  separate  coats,  which  are 
scraped  and  pumiced  until  the  leather  is  perfectly  filled  and 
smooth. 

The  finishing  coat  is  put  on  with  special  care  in  a  room 
kept  closed  and  with  the  floor  wet  to  prevent  dust.  The 
frames  are  then  run  into  an  oven  heated  to  about  175  de- 
gress. In  preparing  this  kind  of  leather  the  manufacturer 
must  give  the  skin  as  high  a  heat  as  it  can  bear,  in  order  to 
dry  the  composition  on  the  surface  as  rapidly  as  possible 
without  absorption,  and  cautiously,  so  as  not  to  injure  the 
fibre  of  the  leather.  It  is  well  nigh  impossible  to  guarantee 
the  permanency  of  patent  leather,  no  matter  how  expensive 
or  how  careful  be  the  preparation,  for  it  has  a  sad  trick  of 
cracking  without  any  justifiable  provocation. 


219 
HOW  TO  LACQUER  BRASS. 

It  is  strange  that  not  one  druggist  out  of  ten  knows  how- 
to  compound  and  put  up  a  first-class  lacquer,  but  depends 
entirely  on  the  manufacturer,  who,  owing  to  the  general  lack 
of  knowledge  regarding  the  matter,  often  imposes  upon  their 
customers,  sending  a  vastly  inferior  article.  Again,  not  one 
customer  in  ten  knows  how  to  apply  lacquer,  and  the  drug- 
gist is  blamed,  when  the  user's  ignorance  is  the  cause  of 
failure.  Let  both  the  dealer  and  the  consumer  keep  the  fol- 
lowing constantly  in  mind  when  selling  or  using  lacquer  : 

Remove  the  last  vestige  of  oil  or  grease  from  the  goods 
to  be  lacquered,  and  do  not  touch  the  work  with  the  fingers. 
A  pair  of  spring  tongs  or  a  taper  stick  in  some  of  the  holes 
is  the  best  way  of  holding. 

Heat  the  work  sufficiently  hot  to  cause  the  brush  to 
smoke  when  applied,  but  do  not  make  hot  enough  to  harm 
the  lacquer. 

Fasten  a  small  wire  across  the  lacquer  cup  from  side  to 
side  to  scrape  the  brush  on  ;  the  latter  should  have  the  ends 
of  the  hairs  trimmed  exactly  even  with  a  pair  of  sharp 
scissors. 

Scrape  the  brush  as  dry  as  possible  on  the  wire,  making  a 
flat,  smooth  point  at  the  same  time. 

Use  the  very  tip  of  the  brush  to  lacquer  with,  go  very 
slow,  and  carry  a  steady  hand. 

Put  on  two  coats  at  least.  In  order  to  make  a  very  dura- 
ble coat,  blaze  off  with  a  spirit  lamp  or  Bunsen  burner,  taking 
special  pains  not  to  burn  the  lacquer. 

If  the  work  looks  gummy,  the  lacquer  is  too  thick  ;  if 
prismatic  colors  show  themselves,  the  lacquer  is  too  thin.  In 
the  former  case,  add  a  little  alcohol ;  in  the  latter,  place  over 
the  lamp,  and  evaporate  to  the  desired  consistency. 

If  the  work  is  cheap,  like  lamp-burners,  curtain  fixtures, 
etc.,  the  goods  may  be  dipped.  For  this  purpose  use  a  bath 
of  nitric  acid,  equal  parts,  plunge  the  goods  in,  hung  on  wire, 
for  a  moment,  take  out  and  rinse  in  cold  water  thoroughly, 
dip  in  hot  water,  the  hotter  the  better,  remove  and  put  in  alco- 
hol, rinse  thoroughly,  and  dip  in  lacquer,  leaving  in  but  a  few 
minutes ;  shake  vigorously  to  throw  off  all  surplus  lacquer, 
and  lay  in  a  warm  place  ;  a  warm  metal  plate  is  the  best  to 
dry.  Do  not  touch  till  cool,  and  the  job  is  done.  Lac- 
quered work  should  not  be  touched  till  cold;  it  spoils  the 
polish. 

Sometimes  drops  will  stand  on  the  work,  leaving  a   spot. 


These  drops  are  merely  little  globules  of  air,  and  can  be 
avoided  by  shaking  when  taken  out. 

The  best  lacquer  for  brass  is  bleached  shellac  and  alco- 
hol ;  simply  this,  and  nothing  more. 

In  the  preparation  of  goods  for  lacquering,  care  should  be 
taken  to  polish  gradually,  /'.  <?.,  carefully  graduate  the  fine- 
ness of  materials  until  the  last  or  finest  finish.  Then,  when 
the  final  surface  is  attained,  there  will  be  no  deep  scratches, 
for,  of  all  things  to  be  avoided  in  fine  work,  are  deep  scratches 
beneath  a  high  polish. 

THE  REAL  INVENTOR  OF  THE  BESSEMER  PRO- 
CESS. 

William  C.  Kelly,  inventor  of  the  Bessemer  process  of 
making  steel,  and  who  died  recently  in  Louisville,  Ky.,  was 
years  ago,  the  proprietor  of  the  Suanee  Iron  Works  and 
Union  Forge,  in  Lyon  County,  Ky.  The  metal  produced  at 
these  works  was  taken  from  the  furnace  to  the  forge,  where 
it  was  converted  into  charcoal  blooms.  These  blooms  had  a 
great  reputation  for  durability  and  quality,  and  were  used 
principally  for  boiler  plates  and  metal.  It  was  while  making 
the  blooms  at  this  place  that  Mr.  Kelly  made  his  great  inven- 
tion of  converting  iron  into  Bessemer  steel,  which  Judge 
Kelly  of  Pennsylvania,  at  the  Masonic  Temple  Theater  last 
fall,  termed  the  greatest  invention  of  the  age.  The  old  pro- 
cess of  making  blooms  was  very  expensive,  owing  to  the 
great  amount  of  charcoal  required  in  its  transformation,  and 
Mr.  Kelly  conceived  the  idea  of  converting  the  metal  into  char- 
coal blooms  without  the  use  of  fuel,  by  simply  forcing  powerful 
blasts  of  atmosphere  up  through  the  molten  metal.  His  idea 
was  that  the  oxygen  of  the  air  would  unite  with  the  carbon 
in  the  metal  and  thus  produce  combustion,  refine  the  metal, 
and,  by  eliminating  the  carbon,  wrought-iron  or  steel  would 
be  produced.  When  he  announced  his  theory  to  his  friends 
and  to  skilled  iron  workers,  they  scoffed,  and  were  struck  with 
astonishment  that  a  man  of  Mr.  Kelly's  learning  and  practical 
iron-making  knowledge  would  suggest  such  an  idea  as  boiling 
metal  without  the  use  of  fuel,  and  by  simply  blowing  air 
through  it. 

His  friends  thought  him  demented,  and  discouraged  him 
from  wasting  his  time  and  money  upon  any  such  visionary 
scheme.  Mr.  Kelly  was  confident  that  his  idea  was  a  good 
one,  and  began  making  experiments,  which  he  kept  up  with 
varying  success  for  ten  years,  but  the  blooms  were  manufac- 
tured without  the  aid  of  fuel.  It  was  generally  known  ae 


221 

" "Kelly's  air  boiling  process,"  and  was  in  daily  use  convert- 
ing iron  into  blooms  at  his  forge.  Mr.  Kelly's  customers 
learned  finally  of  the  process,  and,  not  understanding  it,  they 
advised  him  that  they  would  not  buy  blooms  made  by  any 
but  the  old  and  established  method.  This  was  the  first  diffi- 
culty placed  in  Mr.  Kelly's  way,  and  he  was  consequently 
compelled  to  carry  on  his  work  secretly,  which  subjected  him 
to  many  disadvantages.  Some  English  skilled  workmen  in 
Mr.  Kelly's  employ  were  familiar  with  his  non-fuel  process, 
and  went  back  to  England,  taking  the  secret  with  them. 
Shortly  after  their  arrival  in  Liverpool,  Henry  Bessemer,  an 
English  ironmaster,  startled  the  iron  world  by  announcing 
the  discovery  of  the  same  process  as  Mr.  Kelly's,  and  applied 
for  patents  in  Great  Britain  and  in  the  United  States.  Mr. 
Kelly  at  once  made  his  application  for  a  patent,  and  was 
granted  one  over  Bessemer,  the  decision  being  that  he  was  the 
first  inventor  and  was  entitled  to  the  patent  by  priority. 

The  history  of  this  remarkable  invention  is  a  lengthy  one, 
and  it  is  generally  admitted  by  persons  cognizant  of  the  facts 
in  the  case  that  Bessemer' s  idea  was  secured  from  the  English 
ironworkers  employed  by  Mr.  Kelly.  Certain  it  is,  however, 
that  Mr.  Kelly's  invention  and  patents  have  heaped  honors 
and  wealth  upon  Bessemer,  and  he  has  been  regarded  as 
the  greatest  inventor  of  the  nineteenth  century,  and  the 
proper  credit  was  always  accorded  him.  Mr.  Kelly's  process 
was  but  barely  successful  until  after  it  was  perfected  by  Rob- 
ert Musshult,  a  prominent  English  iron  worker.  Concern- 
ing the  claims  of  the  different  persons,  a  prominent  iron  and 
steel  manufacturer,  the  late  James  Park,  of  Pittsburg,  once 
said:  "  The  world  will  some  day  learn  the  truth,  and  in  ages 
to  come  a  wreath  of  fame  will  crown  William  Kelly,  the  true 
inventor,  and  that  truth  will  never  be  effaced  by  time." 

A  NOVEL  PLANING  MACHINE. 

A  machine  for  planing  the  curved  surfaces  of  propeller 
blades,  so  as  to  render  them  of  uniform  thickness  and  pitch, 
has  been  invented  in  England,  and  is  herewith  described. 
The  principal  feature  is  guiding  and  controlling  the  tool  to 
travel  on  the  curved  surfaces,  by  a  cast-iron  former. 

The  machine  is  provided  with  two  tables,  which  can  be 
rotated  through  a  given  range  by  a  worm-wheel  and  worm, 
so  that  the  inclinations  of  both  tables  can  be  simultaneously 
varied,  and  to  an  equal  degree.  One  of  the  tables  carries  a 
cast-iron  copy  of  the  back  or  front  of  the  blade  it  is  desired 
to  produce,  whilst  on  the  other  table  the  actual  propeller  is 


222 

secure^  one  of  its  blades  occupying  a  similar  position  on  tfcij 
table  to  that  of  the  copy  on  the  other. 

To4r*ure  the  rigidity  of  the  work,  the  table  on  which  the 
propeller  is  fixed  has  its  upper  surface  shaped  to  correspond 
with  thh  form  of  the  blade  on  it,  and  is  finally  brought  to  the 
exact  sh*ipe  necessary  by  a  coating  of  Portland  cement.  A 
cut  y%  i'i;  deep  can  be  taken  without  springing  the  blade. 
The  propeller  is  also  held  by  being  mounted  on  a  duplicate 
of  the  }>ropeller  shaft,  which  is  secured  to  the  table.  The 
cutting  iV;  done  by  a  tool  of  the  ordinary  type,  work  being 
commence)  at  the  top  of  the  blade,  and  a  self-acting 
traverse  fo  \sed  to  feed  the  tool  toward  the  boss. 

The  tool-holder  is  connected  by  a  system  of  levers  with  a 
similar  holder  at  the  other  end  of  the  slide,  carrying  a 
follower,  which  moves  over  the  copy,  and  thus  guides  the 
cutting  tool.  As  the  boss  is  approached,  the  inclination  of 
the  two  tables  to  the  horizontal  is  altered  by  the  worm  gear, 
so  as  to  limit  the  necessary  vertical  motion  of  the  tool.  In 
this  way  all  the  blades  of  the  propeller  may  be  successfully 
machined,  back  and  front,  and  will  then  be  of  identical  form 
and  thickness,  and  set  at  the  same  angle  to  the  propeller 
shaft. 

One  of  the  propellers  lately  turned  out  by  this  machine 
was  6  ft.  \p.  diameter,  with  an  increasing  pitch,  the  mean  of 
which  was  7  ft.  9  in.,  the  thickness  in  the  center  of  the  blades 
varying  from  l/%  in.  at  the  top  to  I  in.  at  the  boss.  The 
breadth  was  21  in.,  and  the  widest  part  and  the  cross  section 
showed  a  regular  taper  from  the  center  line  to  a  knife-edge. 

The  importance  of  accuracy  and  uniformity  in  the  shape 
of  the  blades  of  propellers  for  high-speed  vessels  is  now 
generally  acknowledged,  and  the  machine  we  have  described 
promises  to  form  a  very  useful  addition  to  the  plant  of  a 
modern  marine  engineering  establishment. 

HOW  TO  REMOVE  RUST  FROM  IRON. 
A  method  of  removing  rust  from  iron  consists  in  im- 
mersing the  articles  in  a  bath  consisting  of  a  nearly  saturated 
solution  of  chloride  of  tin.  The  length  of  time  during  which 
the  objects  are  allowed  to  remain  in  the  bath,  depends  on 
the  thickness  of  the  coating  of  rust ;  but  in  ordinary  cases 
twelve  to  twenty-four  hours  is  sufficient.  The  solution 
ought  .not  to  contain  a  great  excess  of  acid  if  the  iron  itself 
is  not  to  be  attacked.  On  taking  them  from  the  bath,  th? 
articles  are  rinsed  in  water  and  afterward  in  ammonia.  The 
iron,  when  thus  treated,  has  the  appearance  of  dull  silver  ; 
i>ut  a  simple  polishing  will  give  it  its  n  r.nal  appearance. 


HOW  TO  ANNEAL  STEEL. 

Owing  to  the  fact  that  the  operations  of  rolling  or  ham- 
mering steel  make  it  very  hard,  it  is  frequently  necessary 
that  the  steel  should  be  annealed  before  it  can  be  conven- 
iently cut  into  the  required  shapes  for  tools. 

Annealing  or  softening  is  accomplished  by  heating  steel 
to  a  red  heat,  and  then  cooling  it  very  slowly,  to  prevent  it 
from  getting  hard  again 

The  higher  the  degree  of  heat  the  more  will  steel  be 
softened,  until  the  limit  of  softness  is  reached,  when  the  steel 
is  melted. 

It  does  not  follow  that  the  higher  a  piece  of  steel  is 
heated  the  softer  it  will  be  when  cooled,  no  matter  how 
slowly  it  may  be  cooled ;  this  is  proved  by  the  fact  that  an 
ingot  is  always  harder  than  a  rolled  or  hammered  bar  made 
from  it. 

Therefore,  there  is  nothing  gained  by  heating  a  piece  of 
steel  hotter  than  a  good  bright  cherry  red  ;  on  the  contrary, 
a  higher  heat  has  several  disadvantages :  if  carried  too  far, 
it  may  leave  the  steel  actually  harder  than  a  good  red  heat 
would  leave  it.  If  a  scale  is  raised  on  the  steel,  this  scale 
will  be  harsh,  granular  oxide  of  iron,  and  will  spoil  the  tools 
used  to  cut  it.  It  often  occurs  that  steel  is  scaled  in  this  way, 
and  then,  because  it  does  not  cut  well,  it  is  customary  to  heat 
it  again,  and  hotter  still,  to  overcome  the  trouble,  while  the 
fact  is,  that  the  more  this  operation  is  repeated,  the  harder 
the  steel  will  work,  because  of  the  hard  scale  and  the  harsh 
grain  underneath.  A  high  scaling  heat,  continued  for  a 
little  time,  changes  the  structure  of  the  steel,  destroys  its 
crystalline  property,  makes  it  brittle,  liable  to  crack  in  hard- 
ening, and  impossible  to  refine. 

Again,  it  is  a  common  practice  to  put  steel  into  a  hot  fur- 
nace at  the  close  of  a  day's  work,  and  leave  it  there  all  night. 
This  method  always  gets  the  steel  too  hot,  always  raises  a 
scale  on  it,  and,  worse  than  either,  it  leaves  it  soaking  in  the 
fire  too  long,  and  this  is  more  injurious  to  steel  than  any  other 
operation  to  which  it  can  be  subjected. 

A  good  illustration  of  the  destruction  of  crystalline  struc- 
ture by  long-continued  heating  may  be  had  by  operating  on 
chilled  cast-iron. 

If  a  chill  be  heated  red  hot  and  removed  from  the  fire  as 
soon  as  it  is  hot,  it  will,  when  cold,  retain  its  peculiar  crystal- 
line structure;  if  now  it  be  heated  red  hot,  and  left  at  a 
moderate  red  for  several  hours;  in  short,  if  it  be  treated  as 
Steel  often  is,  and  be  left  in  a  furnace  over  night,  it  will  be 


224 

found,  when  cold,  to  have  a  perfect  amorphous  structure, 
every  trace  of  chill  crystals  will  be  gone,  and  the  whole  piece 
be  non-crystalline  gray  cast-iron.  If  this  is  the  effect  upon 
coarse  cast -irons,  what  better  is  to  be  expected  from  fine  cast- 
steel  ? 

A  piece  of  fine  tap  steel,  after  having  been  in  a  furnace 
over  night,  will  act  as  fallows: 

It  will  be  harsh  in  the  lathe  and  spoil  the  cutting  tools. 

When  hardened,  it  will  almost  certainly  crack;  if  it  does 
not  crack,  it  will  have  been  a  remarkably  good  steel  to  begin 
with.  When  the  temper  is  drawn  to  the  proper  color  and  the 
tap  is  put  into  use,  the  teeth  will  either  crumble  off  or  crush 
down  like  so  much  lead. 

Upon  breaking  the  tap,  the  grain  will  be  coarse  and  the 
steel  brittle. 

To  anneal  any  piece  of  steel,  heat  it  red  hot;  heat  it  uni- 
formly and  heat  it  through,  taking  care  not  to  let  the  ends 
and  corners  get  too  hot. 

As  soon  as  it  is  hot,  take  it  out  of  the  fire,  the  sooner  the 
better,  and  cool  it  as  slowly  as  possible.  A  good  rule  for 
heating  is  to  heat  it  at  so  low  a  red  that,  when  the  piece  is 
cold,  it  will  still  show  the  blue  gloss  of  the  oxide  that  was  put 
there  by  the  hammer  or  rolls. 

Steel  annealed  in  this  way  will  cut  very  soft;  it  will  harden 
very  hard,  without  cracking,  and,  when  tempered,  it  will  be 
very  strong,  nicely  refined,  and  will  hold  a  keen,  strong  edge. 

THE  BURSTING   AND   COLLAPSING    PRESSURE 
OF  SOLID  DRAWN  TUBES. 

The  following  table  gives  the  bursting  and  collapsing 
pressure  of  solid  drawn  tubes: 

Collapsing 

Difference. 
1500 
1350 
1000 

1700 
1400 
1400 

IOOO 

1600 

In  this  table  it  will  be  noticed  that  the  bursting  strength 
exceeds  the  collapsing  strength,  and  that  the  difference  in- 
creases with  the  diameter,  as  shown  in  the  last  column. 


Diameter. 

-<i/ 

Bursting 
Pressure. 
4800 

Collapsing 
Pressure. 
33OO 

3/+  ' 
31/6  

d^OO 

31  SO 

3 

45OO 

35°° 

ix 

S2OO 

3  CQO 

2*4  

5OOO 

3600 

a#., 

tjQOO 

4.SOO 

2         

5900 

4900 

I*. 

s6oo 

40CO 

225 

MINERAL  WOOL. 

Mineral  wool  is  the  name  of  an  artificial  product  now 
used  for  a  great  variety  of  purposes,  chiefly,  however,  as  a 
non-conductor  for  covering  steam  surfaces  of  whatever  char- 
acter. It  is  largely  used  for  this,  and  the  underground  steam 
pipes  of  the  New  York  Steam  Company  are  insulated  with  it. 

Mineral  wool  is  made  by  converting  vitreous  substances 
into  a  fibrous  state.  The  slag  of  blast  furnaces  affords  a 
large  supply  of  material  suitable  for  this  purpose.  The 
product  thus  obtained  is  known  as  slag  wool.  For  the 
reason  that  slag  is  seldom  free  from  compounds  of  sulphur, 
which  are  objectionable  in  the  fiber,  a  cinder  is  prepared 
from  which  is  made  rock  wool.  These  products  comprise 
the  two  kinds  of  mineral  wool;  they  are  not  to  be  dis- 
tinguished from  it,  but  from  each  other. 

The  resemblance  of  the  fibers  to  those  of  wool  and 
cotton  has  given  the  names  of  mineial  M^OO!  and  silicate 
cotton  to  the  material,  but  the  similarity  in  looks  is  as  far  as 
the  comparison  can  be  followed.  The  hollow  and  joined 
structure  of  the  organic  fiber,  which  gives  it  flexibility 
and  capillary  properties,  is  wanting  in  the  mineral  fibre. 
The  latter  is  simply  finely-spun  glass  of  irregular  thickness, 
without  elasticity  or  any  such  appendages  as  spicules,  which 
would  be  necessary  for  weaving  purposes.  The  rough  sur- 
faces and  markings  of  the  fiber  can  only  be  detected  under  a 
strong  magnifying  glass. 

Aside  from  its  uses  as  covering  for  hot  surfaces,  it  is  also 
largely  employed  for  buildings.  A  filling  of  mineral  wool  in 
the  ground  floor,  say  two  inches  thick,  protects  against  the 
dampness  of  cellar ;  in  the  outside  walls,  from  foundation  to 
peak,  between  the  studding,  it  will  prevent  the  radiation  of 
the  warmth  of  interior,  and  will  destroy  the  force  of  winds, 
which  penetrate  and  cause  draughts;  in  the  roof  it  will  re- 
tain the  heat  which  rises  through  stair-wells,  bringing  about 
regularity  of  temperature  in  cold  weather ;  the  upper  rooms 
will  not  receive  the  heat  of  the  summer  sun,  and  store  it  up 
for  the  occupants  during  the  night,  but  remain  as  cool  as 
those  on  the  floor  below  ;  the  water  fixtures  in  bath-rooms, 
closets  and  pantries  will  not  be  exposed  to  extremes  of  heat 
and  cold. 

Analysis  of  mineral  wool  shows  it  to  be  a  silicate  of 
magnesia,  lime,  alumina,  potash  and  soda.  The  slag-wool 
contains  also  some  sulphur  compounds.  There  is  nothing 
organic  in  the  material  to  decay  or  to  furnish  food  and  com- 
fort to  insects  and  vermin  ;  on  the  other  hand,  the  fine  fibers 


226 

of  glass  are  irritating  to  anything  which  attempts  to  burrow 
in  them.  New  houses  lined  with  mineral  wool  will  not  be- 
come infested  with  animal  life,  and  old  walls  may  be  ridden 
of  their  tenants  by  the  introduction  of  it. 

Mineral  wool  is  largely  used  for  car  linings,  in  which 
service  it  reduces  the  noise  of  travel  greatly.  Aside  from 
those  mentioned,  it  can  be  applied  generally  in  the  arts  for 
all  purposes  where  a  non-conductor  or  a  shield  is  required, 
and  ihe  experience  of  several  years  show  that  it  is  both 
serviceable  and  cheap. 

NICKEL  PLATING  SOLUTION. 

,  According  to  the  Bulletin  Internationale  de  F Electricite% 
the  following  solution  is  employed  for  nickel  plating  by  sev- 
eral firms  in  Hainault.  It  is  said  to  give  a  thick  coating  of 
nickel  firmly  and  rapidly  deposited.  The  composition  of  the 
bath  is  as  follows: 

Sulphate  of  nickel ; I         Ib. 

Neutral  tartrate  of  ammonia 1 1 . 6     oz. 

Tannic  acid  with  ether 08  oz. 

Water 16    pints. 

The  natural  tartrate  of  ammonia  is  obtained  by  saturat- 
ing tartaric  acid  solution  with  ammonia.  The  nickel  sul- 
phate to  be  added  must  be  carefully  neutralized.  This  hav- 
ing been  done,  the  whole  is  dissolved  in  rather  more  than 
three  pints  of  water,  and  boiled  for  about  a  quarter  of  an 
hour.  Sufficient  water  is  then  added  to  make  about  sixteen 
pints  of  solution,  and  the  whole  is  finally  filtered.  The 
deposit  obtained  is  said  to  be  white,  soft  and  homogeneous. 
It  has  no  roughness  of  surface,  and  will  not  scale  off,  pro- 
vided the  plates  have  been  thoroughly  cleaned.  By  this 
method  good  nickel  deposits  can  be  obtained  on  either  the 
rough  or  prepared  casting,  and  at  a  net  cost  which,  we  are 
told,  barely  exceeds  that  of  copper  plating. 

A  NEW  ALLOY. 

An  alloy,  the  electrical  resistance  of  which  diminishes 
with  an  increase  of  temperature,  has  recently  been  discovered 
by  Mr.  Edward  Weston.  It  is  composed  of  copper,  man- 
ganese and  nickel.  Another  alloy,  due  to  the  same  investi- 
gator, the  resistance  of  which  is  practically  independent  of  the 
temperature,  consists  of  seventy  parts  of  copper,  combined 
with  thirty  of  ferro-manganese. 


227 

PROOF  OK  THE  EARTH'S  MOTION. 

Any  one  can  prove  the  rotary  motion  of  the  earth  on  its 
axis  by  a  simple  experiment. 

Take  a  good-sized  bowl,  fill  it  nearly  full  of  water  and 
place  it  upon  the  floor  of  a  room  which  is  not  exposed  to 
shaking  or  jarring  from  the  street. 

Sprinkle  over  the  surface  of  the  water  a  coating  of  lyco- 
podium  powder,  a  white  substance  which  is  sometimes  used 
for  the  purposes  of  the  toilet,  and  which  can  be  obtained  at 
almost  any  apothecary's.  Then,  upon  the  surface  of  this 
coating  of  powder,  make  with  powdered  charcoal  a  straight 
black  line,  say  an  inch  or  two  inches  in  length. 

Having  made  this  little  black  mark  with  the  charcoal 
powder  on  the  surface  of  the  contents  of  the  bowl,  lay  down 
upon  the  floor,  close  to  the  bowl,  a  stick  or  some  other 
straight  object,  so  that  it  shall  be  exactly  parallel  with  a 
crack  in  the  floor,  or  with  any  stationary  object  in  the  room 
that  will  serve  as  well. 

Leave  the  bowl  undisturbed  for  a  iew  hours,  and  then 
observe  the  position  of  the  black  mark  with  reference  to  the 
object  it  was  parallel  with. 

It  will  be  found  to  have  moved  about,  and  tohavemoved 
from  east  to  west,  that  is  to  say,  in  that  direction  opposite 
to  that  of  the  movement  of  the  earth  on  its  axis. 

The  earth,  in  simply  revolving,  has  carried  the  water  and 
everything  else  in  the  bowl  around  with  it,  but  the  powder 
on  the  surface  has  been  left  behind  a  little.  The  line  will 
always  be  found  to  have  moved  from  east  to  west,  which  is 
perfectly  good  proof  that  everything  else  has  moved  the 
other  way. 

WHY  THE  COMPASS  VARIES. 

The  compass,  upon  which  the  sailor  has  to  depend,  is 
subject  to  many  errors,  the  chief  of  which  are  variation  and 
deviation  ;  that  is,  the  magnetic  needle  rarely  points  to  the 
true  north,  but  in  a  direction  to  the  right  or  left  of  north, 
according  to  its  error  at  the  time  and  place.  The  deviation 
of  the  compass  comprises  those  errors  which  are  local  in 
their  character ;  that  is,  due  to  the  effect  of  immediately 
surrounding  objects,  such  as  the  magnetism  of  the  ship  itself; 
this  is  sometimes  very  great  in  an  iron  ship. 

The  variation  of  the  compass  varies  with  the  position  of 
the  ship,  as  shown  by  these  curves  of  variation.  Thus,  from 
Cape  Race  to  New  York  the  variation  of  the  compass  changes 
from  30°  W.  to  less  than  10°  W.  ;  and  from  Cape  Race  to 


22S 

New  Orleans  from  30°  W.  to  more  than  5°  E.,  the  line  of 
no  variation  being  indicated  by  the  heavier  double  line 
stretching  from  the  coast  near  Charleston  down  through 
Puerto  Rico  and  the  Windward  Islands  to  the  northeastern 
coast  of  South  America. 

To  illustrate  these  variation  curves  more  clearly,  a  chart 
has  been  made  ujxm  which  variation  curves  are  plotted  for 
.each  degree.  This  illustrates  very  strikingly  the  positions 
of  the  magnetic  poles  of  the  earth,  which  do  not  by  any 
means  coincide  with  the  geographic  poles.  On  the  contrary, 
there  are  two  northern  magnetic  poles  and  two  southern;  up 
north  of  Hudson's  Bay,  at  the  point  where  these  curves 
converge,  there  is  one  magnetic  pole,  and  another  to  the 
northward  of  Siberia.  Similarly,  there  are  two  in  the  south- 
ern hemisphere,  an  I  these  four  poles  of  this  great  magnet, 
the  earth,  are  constantly  but  slowly  shifting  their  positions, 
and  just  so  constantly  and  surely  does  the  magnetic  needle 
c>bey  these  varying,  but  ever-present  forces,  seldom  pointing 
toward  the  pole  which  man  has  marked  off  on  his  artificial 
globe,  but  always  true  to  the  great  natural  laws  to  which 
alone  it  owes  allegiance.  The  small  figures  with  plus  and 
minus  signs  at  various  places  on  this  chart  indicate  the  yearly 
rate  of  change  of  variation,  and  this  rate  varies  at  different 
positions  on  the  chart.  Thus,  near  the  Cape  Verde  Islands 
it  is  p'us  j90  ;  here  the  variation  increases  ^  of  a  minute  a 
year;  farther  to  the  southward,  near  the  South  American 
coast,  it  is  plus  7^,,  an  I  to  the  northward,  near  the  Irish 
Channel,  it  is  minus  7,*,,-.  Fortunately,  however,  these 
changes  are  STiall  and  comparatively  regu'ar,  and  their 
cumulative  effect  can  be  allowed  for,  when  large  enough  to 
make  it  necessary  to  do  so 

COST  OF  ELECTRIC  STREET  RAILWAYS. 

One  of  the  street  railways  in  New  York  is  about  running 
its  cars  to  Harlem  by  an  electric  motor.  Experts  engaged 
in  perfecting  the  scheme  have  made  an  exhibit,  showing  that 
it  can  be  done  at  a  cost  of  about  two-thirds  of  the  amount 
required  to  run  over  the  sane  route  with  horses  or  cable. 
There  will  be  sixteen  batteries  inclosed  in  one  wagon,  which 


will   furnish  sufficient    power   for   two   round    trips.      Sixty 

w  in  operation  in  the 
States.     Of  the  ultimate   success,   there  can    be  but   little 


. 
electric  street  railways  are  now  in  operation  in  the  United 


doubt  ;  the  one  question  of  any  special  importance  upon 
which  the  experts  differ  is  the  superiority  of  any  particular 
system. 


229 

KEEPING  TOOLS. 

Keep  your  tools  handy  and  in  good  condition.  This  applies 
everywhere  and  in  every  place,  from  the  smallest  shop  to  the 
greatest  mechanical  establishment  in  the  world.  Every  tool 
should  have  its  exact  place,  and  should  always  be  kept  there 
when  not  in  use. 

Having  a  chest  or  any  receptacle  with  a  lot  of  tools  thrown 
into  it  promiscuously,  is  just  as  bad  as  putting  the  notes  into 
an  organ  without  regard  to  their  proper  place.  If  a  man 
wants  a  wrench,  chisel  or  hammer,  it's  somewhere  in  the  box 
or  chest,  or  somewhere  else,  and  the  search  begins.  Some- 
times it  is  found  —  perhaps  sharp,  perhaps  dull,  maybe 
broken;  and  by  the  time  it  is  found  he  has  spent  time  enough 
to  pay  for  several  tools  of  the  kind  wanted. 

The  habit  of  throwing  every  tool  down,  anyhow,  and  in 
any  way,  or  any  place,  is  one  of  the  most  detestable  habits  a 
man  can  possibly  get  into.  It  is  only  a  matter  of  habit  to 
correct  this.  Make  an  inflexible  end  of  your  life  to  "have  a 
place  for  everything  and  everything  in  its  place. " 

It  may  take  a  moment  more  to  lay  a  tool  up  carefully 
after  using,  but  the  time  is  more  than  equalized  when  you 
want  to  use  it  again,  and  so  it  is  time  saved.  Habits,  either 
good  or  bad,  go  a  long  ways  in  their  influence  on  men's 
lives,  and  it  is  far  better  to  establish  and  firmly  maintain  a 
good  habit,  even  though  that  haoit  has  no  special  bearing 
on  the  moral  character,  yet  all  habits  have  their  influence. 

Keeping  tool?  in  good  order,  and  ready  to  use,  is  as  neces- 
sary as  keeping  them  in  the  proper  place.  To  take  up  a  dull 
*aw,  or  a  dull  chisel,  and  try  to  do  any  kind  of  work  with  it, 
is  worse  than  pulling  a  boat  with  a  broom,  and  it  all  comes 
from  just  the  same  source  as  throwing  down  tools  carelessly 
—  habit,  nothing  more  or  less.  To  say  you  have  no  time  to 
sharpen  is  worse  than  outright  lying,  for,  if  you  have  time  to 
use  a  dull  tool,  you  have  time  to  put  it  in  good  order. 

AN  IMPROVED  SCREW-DRIVER. 
A  screw-driver  has  been  made  in  Philadelphia  with  the 
handle  in  two  parts,  said  parts  being  capable  of  rotating  one 
upon  the  other.  A  stop-pin  and  pawl  limit  the  movement  of 
the  shank  in  one  direction,  while  the  top  of  the  handle  will 
move  backward  without  turning  the  shank.  The  mechanism 
appears  to  be  very  similar  to  the  principle  of  a  stem-winding 
watch. 


23° 

THE  EFFECT  OF    MAGNETISM    ON    WATCHES, 

At  a  meeting  of  the  Western  Railway  Club,  Mr.  E.  M. 
Herr,  superintendent  of  telegraph  of  the  Chicago,  Burling- 
ton &  Quincy  Railroad,  read  the  following  paper  : 

A  magnet  is  a  body,  usually  of  steel,  having  the  property, 
when  delicately  poised  and  free  to  turn,  of  pointing  toward 
the  north,  and  of  attracting  and  causing  to  adhere  to  its 
ends  or  poles,  pieces  of  iron,  steel,  and  some  other  substances. 
Materials  which  are  attracted  by  a  magnet  are  called  mag- 
netic, and  it  is  because  the  rapidly  moving  parts  of  a  watch 
are  in  general,  made,  in  part  at  least,  of  magnetic  material, 
that  these  timepieces  are  affected  by  that  peculiar  force 
magnetism. 

Were  magnetic  substances  only  affected  while  a  magnet 
is  near  them,  there  would  be  little  difficulty  as  far  as 
watches  are  concerned.  Such,  unfortunately,  is  not  the 
case,  as  certain  materials,  steel  more  than  any  other,  are 
not  only  attracted  by  a  magnet,  but  become  themselves  per- 
manent magnets  when  brought  into  contact  with  or  even  in 
the  vicinity  of  a  magnetized  body.  It  is  to  the  latter  prop- 
erty of  steel,  namely,  becoming  permanently  magnetized  by 
the  approach  of  a  magnet  without  coming  in  contact  in  any 
way  with  it,  that  causes  trouble  with  watches. 

Again,  a  small  piece  of  steel  is  much  more  easily  mag- 
netized than  a  large  one;  consequently,  the  small  and  deli- 
cate parts  of  a  watch  are  most  likely  to  be  affected.  These  are 
found  in  the  balance  wheel  and  staff,  hair  spring,  fork  and 
escape  wheel,  and  are  the  very  ones  in  which  magnetism 
causes  trouble  on  account  of  the  extreme  accuracy  and  reg- 
ularity with  which  they  must  perform  their  movements.  It 
is,  in  fact,  upon  the  uniformity  in  the  motion  of  the  balance 
wheel,  that  the  timekeeping  qualities  of  the  watch  depend. 

In  a  magnetized  watch  this  wheel,  as  well  as  all  other 
steel  parts,  become  permanent  magnets,  each  tending  to  place 
itself  in  a  north  and  south  line,  and  also  to  attract  and  to  be 
attracted  by  the  others;  all  of  which,  it  is  hardly  nece  sary 
to  add,  tends  to  affect  its  reliability  as  a  timepiece.  How 
small  a  variation  in  each  vibration  of  the  balance  wheel  will 
cause  a  serious  error  in  the  daily  rate  of  a  watch,  is  easily 
realized  when  attention  is  given  for  a  moment  to  the  number 
of  double  vibrations  this  wheel  makes  in  24  hours. 

This  varies  in  different  watches  from  174.000  to  216,000, 
and  the  variation  of  a  single  vibration  in  this  number  will 
cause  a  greater  error  than  is  sometimes  found  in  the  best 
watch  movements.  It  is  therefore  true  that  the  variation  in 


each  vibration  of  the  balance  wheel  of  1-200,000  part  of 
thetimeof  such  vibration,  or  in  actual  time  about  the  1-500,- 
ooo  part  of  a  second,  will  prevent  the  watch  rating  as  a 
strictly  first-class  time  piece. 

I  wish  to  state,  however,  that  there  are  very  few  watches 
made  of  ordinary  materials  which  are  absolutely  free  from 
magnetism.  This  may  seem  like  a  sweeping  statement,  but, 
after  taking  considerable  pains  to  verify  or  disprove  of  it,  I 
am  convinced  that  it  is  substantially  correct. 

Why  this  should  be  so  becomes  evident  when  we  consider 
that  a  few  sharp  blows  upon  a  piece  of  steel  held  in  the  di- 
rection of  a  dipping  needle  suffice  to  sensibly  magnetize  it,  and 
then  think  of  the  numerous  mechanical  operations  that  have 
to  be  performed  upon  each  small  piece  of  steel  in  the  moving 
parts  of  a  watch  before  it  becomes  a  finished  product. 

In  order  to  determine,  if  possible,  to  what  extent 
magnetism  prevails  in  watches,  I  have  examined  and  tested 
for  magnetism  28  watches  carried  by  persons  other  than  train 
or  engineer  men,  with  the  following  result  :  Three  were  very 
seriously  magnetized  ;  one  to  such  an  extent  that  it  could  not 
be  regulated  closely  ;  twenty  barely  perceptibly  affected, 
possibly,  but  the  normal  amount  due  to  the  process  of 
manufacture,  and  in  but  four  could  no  magnetism  be 
detected. 

On  account  of  the  steel  parts  of  a  locomotive  being 
magnetized  during  the  process  of  construction,  and  by  severe 
usage  in  a  similar  manner  to  those  of  a  watch,  it  has  been 
claimed  that  the  watches  of  engineers  are  constantly  subjected 
to  the  action  of  the  magnetic  forces,  and  cannot  therefore 
keep  as  good  time  as  other  watches. 

I  have  examined  for  magnetism  the  different  parts  of  a 
number  of  locomotives  in  actual  service,  and,  although  they 
were  in  general  found  to  be  magnetic,  they  are  so  slightly 
charged  as  to  render  it  almost  certain  they  could  have  no 
influence  upon  the  rate  of  a  watch,  and  would  surely  produce 
less  effect  upon  it  than  the  originally  slightly  magnetized 
parts  of  the  watch  itself.  That  this  amounts  to  practically 
nothing,  is  proven  by  the  large  number  of  finely  rated 
watches  now  in  use  in  which  magnetism  is  apparent. 

As  proof  of  the  statement  that  engine-men's  watches  are 
not,  as  a  rule,  more  highly  charged  with  magnetism  than 
those  of  men  engaged  in  other  occupations,  the  watches  of 
twenty  locomotive  engineers  were  tested.  Of  these  none 
were  found  heavily  charged  with  magnetism;  but  two  more 
than  normal;  twelve  with  a  barely  perceptible  charge,  and 
in  six  none  could  be  detected,  showing  actually  less  magnet- 


232 

ism  in  these  than  in  the  twenty-eight  watches  previously 
examined,  none  of  which  were  carried  on  a  locomotive,  a 
result  probably  due  to  the  fact  that  engineers,  as  a  rule,  are 
very  careful  of  their  watches,  and  are  less  apt  to  bring  them 
in  dangerous  proximity  to  a  dynamo  than  those  not  con- 
cerned in  running  trains,  and  in  whom  a  well-regulated  watch 
is  less  important.  This,  I  take  it,  would  surely  be  the  case 
did  they  all  understand  that  a  watch  is  likely  to  be  entirely 
disabled  by  bringing  it  near  a  dynamo  or  motor  in  opera- 
tion. It  therefore  seems  important  that  all  to  whom  Accu- 
rate time  is  a  necessity,  should  be  carefully  instructed  as  to 
where  the  danger  lies. 

So  much  has  recently  been  written  about  the  magnetiz- 
ing of  watches  that  many  persons  approach  any  kind  of  elec- 
trical apparatus  with  caution.  Even  a  battery  of  ordinary 
gravity,  or  LeClanche  cells,  is  regarded  with  suspicion, 
while  a  storage  battery  is  thought  almost  as  dangerous  as  a 
dynamo. 

Others,  on  the  other  hand,  do  not  even  know  that  a 
dynamo  is  dangerous  to  watches.  It  should  be  borne  in 
mind  that  it  is  not  electricity  which  affects  watches,  but 
magnetism,  and  that  magnets  are  the  seats  of  danger.  It  is 
the  powerful  electro-magnets  in  dynamos  and  motors  that 
magnetize  watches,  and  not  the  strong  currents  of  electricity 
generated  or  consumed  by  them.  True,  there  is  a  mag- 
netic field  about  every  current  of  electricity,  but  it  is  so 
very  slight  that  no  effect  is  produced  on  watches  worn  in  the 
pocket. 

Having  spoken  of  the  evils  of  magnetism  in  watches,  it 
is,  perhaps,  proper  to  add  a  few  words  regarding  its  preven- 
tion. The  best  and  most  certain  way  to  prevent  a  watch 
becoming  magnetized  is  to  never  allow  it  to  come  near  a 
magnet.  Unfortunately,  in  the  present  age,  this  is  a  diffi- 
cult matter,  as  no  one  can  say  how  soon  they  may  find  it 
necessary  to  be  in  the  vicinity  of  a  dynamo  in  operation  or 
be  seated  in  a  car  propelled  by  an  electro-motor. 

The  only  practical  protection  to  watches  from  magnetism 
of  which  I  have  been  able  to  learn  consists  essentially  of  a 
cup-like  casing  of  very  pure  soft  iron  surrounding  the  works 
of  the  watch,  which  is  known  as  the  anti-magnetic  shield. 
That  this  device  is  a  protection  from  the  effects  of  magnet- 
ism upon  watches,  there  can  be  no  doubt,  but  that  it  pre- 
vents magnetizing  under  all  circumstances,  even  its  inventor, 
I  believe,  does  not  claim. 

It  therefore  becomes  important  to  know  how  far  our 
watches  are  safe  when  supplied  with  this  protection,  and 


23} 

wnere  to  draw  the  danger  line  for  the  protected,  as  well  as 
the  unprotected  watch.  In  order  to  throw  some  light  upon 
this  question,  the  following  tests  were  made: 

First,  to  disc  >ver  to  whit  extent  magnetic  bodies  placed 
within  the  shield  were  protected  from  external  magnetic 
forces  ;' second,  in  how  strong  a  magnetic  field  it  was  neces- 
sary to  place  a  watch  protected  by  this  device  to  effect  its 
rate  by  magnetization. 

While  no  pretense  of  scientific  accuracy  or  precision  was 
made  in  these  tests,  it  is  believed  they  are  sufficiently  accu- 
rate for  scientific  purposes. 

The  first  test  was  made  by  filling  an  inverted  shield  half 
fall  of  water,  on  the  surface  of  which  a  very  light  magnetized 
steel  needle  was  caused  to  float.  In  a  similarly  shaped  cup, 
made  of  porcelain,  another  needle,  in  all  respects  like  the 
first,  was  also  floated.  A  horseshoe  magnet  was  then 
brought  near  each,  and  found  to  affect  each  needle  equally, 
at  the  following  distances  :  in  shield,  6  in.  ;  in  porcelain  cup, 
13^2  in. 

Distance  below  a  3/^-in.  wooden  board,  upon  which  shield 
and  cup  were  placed,  at  which  needles  could  be  just  reversed 
by  magnet-— in  shield,  3^  in.  ;  in  porcelain  cup,  %%  in. 
With  just  enough  water  to  cover  the  bottom  of  shield,  the 
following  distances  for  equal  effects  were  observed  :  first 
'exposure  in  shield,  8  in.  :  first  exposure  in  porcelain  cup, 
20  in.  ;  second  exposure  in  shield,  12  in.  :  second  exposure 
in  porcelain  cup,  30  inches. 

Since  the  intensity  of  a  magnetic  force  varies  inversely  as 
the  square  of  the  distance,  the  above  results  indicate  that  to 
produce  like  effects,  at  equal  distances,  magnetic  forces  from 
five  to  six  times  as  strong  would  be  required,  with  bodies 
inclosed  within  the  shield,  than  with  those  not  so  protected. 

The  second  test  was  made  with  watches  of  different 
makes,  all  furnished  with  the  shield.  Space  will  not  permit 
my  going  into  the  details  of  these  tests,  which  extended  over 
several  months.  I  will  only  say  that  they  in  general  con- 
sisted in  obta' ling  the  rating  and  perfoimance  of  the  watch 
before  and  afttr  it  was  exposed  to  magnetic  influences.  The 
exposure  consisted  in  placing  it  nearer  and  nearer  to  the  pole 
pieces  of  a  powerful  arc  light  dynamo  and  bbserving  the 
rate  before  and  after  each  exposure.  After  many  tests  of 
this  kind,  the  conclusion  wr.s  reached  that  a  watch  carefully 
and  properly  shielded  could  be  safely  placed  not  nearer  than 
4  in.  to  the  pole  pieces  of  a  23  arc  light  Ball  dynamo. 
When  brought  nearer  they  were  without  exception  magnet- 


234 

ized  to  a  greater  or  less  degree,  the  amount  depending 
largely  upon  the  time  of  such  exposure. 

Watches  are  now  being  made,  however,  which  it  is 
claimed  are  entirely  non-magnetic  and  unaffected  by  the 
strongest  magnetic  fields  met  with  in  practice.  -Several 
such  watches  were  also  examined  and  tested.  They  were 
furnished  with  a  balance-wheel,  hair-spring,  fork  and  escape 
wheel  made  of  an  alloy  of  non-magnetic  metals  in  which 
palladium  is  the  principal  component.  The  first  of  these 
watches  tested  was  furnished  only  with  a  non-magnetic  bal- 
ance and  hair-spring,  and  had  a  steel  fork  and  escape  wheel. 
This  watch  is  instantly  stopped  when  brought  near  a  power- 
ful dynamo. 

Other  movements  were  then  tried,  in  which  all  of  the 
rapidly  moving  parts  were  of  non-magnetic  material.  These 
could  not  be  stopped  by  the  field  magnets  of  the  most 
powerful  arc  light  dynamos,  although  when  placed  in  actual 
contact  with  the  pole  piece  the  balance-wheel  was  seen  to 
vibrate  less  freely,  probably  due  to  the  attraction  of  the 
staff  and  pivots,  which  were  of  steel.  The  rate  of  the 
watch  was  not,  however,  altered  by  this  test. 

A  hair-spring  made  of  this  non-magnetic  alloy  was  als» 
delicately  suspended  in  still  air  and  subjected  to  the-  action 
of  a  powerful  horseshoe  magnet  without  developing  the 
slightest  observable  magnetic  effect. 

One  of  our  best -known  American  watch  manufacturing 
firms  is  now  making  a  non-magnetic  watch  on  a  plan  similar 
to  that  just  described  ;  others  will  probably  soon  follow, 
hastening  the  day  when  a  watch  thoroughly  protected  or 
inherently  insensible  to  magnetism  will  be  as  common,  and 
considered  as  necessary  to  the  successful  keeping  of  correct 
time  as  'he  adjustment  for  temperature  and  position  is 
already. 

HOW  BARRELS  ARE  MADE. 

Barrels  are  now  being  made  of  hard  and  soft  wood,  each 
alternate  stave  being  of  the  soft  variety,  and  slightly  thicker 
than  the  hard-wood  stave.  The  edges  of  the  staves  are  cut 
square,  and,  when  placed  together  to  form  the  barrel,  the  out- 
sides  are  even,  and  there  is  a  V-shaped  crack  between  each 
stave  from  top  to  bottom.  In  this  arrangement  the  operation 
of  driving  the  hoops  forces  the  edges  of  the  hard  stave  into 
the  soft  ones,  until  the  cracks  are  closed,  and  the  extra  thick- 
ness of  the  latter  causes  the  inner  edges  to  lap  over  those  of 
of  tin-1  h..rd-wood  staves,  thus  making  the  joints  dorbly 


FACTS  ABOUT  IRON  CASTINGS. 

Some  experience  of  the  changes  of  shape  which  castings 
undergo  by  reason  of  shrinkage  strains  is  necessary,  in  order 
to  proportion  them  correctly.  I  have  seen  numerous  massive 
and  very  strong  looking  castings  fracture  during  cooling,  or  a 
long  time  afterward  while  lying  in  the  yard  untouched,  or 
while  being  machined  ;  the  reason  being  that  excessive  con- 
traction in  one  portion  had  put  adjacent  parts  into  a  condition 
of  great  tension.  By  putting  an  excess  of  metal  into  some 
vulnerable  point  of  a  casting,  is  introduced  an  element  of 
weakness,  and  almost  a  certainty  of  its  breaking  by  reason  of 
the  internal  shrinkage  strains.  It  is  not  the  excess  of  metal 
in  itself  which  gives  rise  to  these  strains,  but  the  position  in 
which  it  is  placed  relatively  to  other  sections.  Thus  a  lump 
of  metal  cast  in  juxtaposition  to  a  thinner  portion  will  not 
break  the  latter,  so  long  as  it  is  able  to  shrink  freely  upon 
itself.  But  if  placed  between  two  thinner  portions,  it  may 
fracture  them  by  its  shrinkage.  Hence  the  great  aim  is  to  so 
design  castings  that  all  portions  thereof  thall  cool  down  with 
approximate  uniformity.  A  founder  learns  much  from  the 
behavior  of  cast-iron  pulleys  and  light  wheels.  As  they  are 
so  light  and  weak,  proportioning  must  be  correctly  observed, 
and  when  customers  ask  fora  "  good,  strong  boss"  or  "  strong 
arms,"  the  request  is  one  which,  if  complied  with  in  the 
manner  described ;  that  is,  by  unduly  increasing  the  metal, 
will  either  fracture  the  pulley  or  wheel,  or  bring  it  near 
to  breaking  limit.  In  alt  castings  "strong'*  is  a  relative 
term,  that  form  or  size  being  strongest  which  harmonizes 
as  regards  general  proportions.  In  a  light  pulley,  three 
different  conditions  may  exist:  i.  All  parts  may  cool 
down  alike,  or  nearly  so  ;  2.  The  rim  may  cool  long  before 
the  arms  and  boss;  3.  The  arms  and  boss  may  cool  before 
the  rim.  in  the  first  case,  the  pulley  will  be  strong  and  safe. 
In  the  second,  the  rim,  in  cooling,  will  set  rigidly,  but  the 
arms  and  boss  will  continue  shrinking,  each  arm  exerting  an 
inward  pull  on  the  rim,  and  various  results  may  follow. 
First,  the  strain  may  simply  cause  the  arm  to  straighten; 
or,  in  less  favorable  conditions,  and  especially  if  straight 
arms,  or  arms  but  slightly  curved,  be  used,  the  arms  may 
fracture  near  the  rim,  but  seldom  near  the  boss.  Or,  if  the 
rim  be  weaker  than  the  arm,  fracture  will  take  place,  or  the 
pulley  may  be  turned,  and  then  break.  ,  In  the  third  case,  the 
arms  and  boss  cooling  before  the  rim,  they  are  compressed 
by  the  shrinkage  of  the  latter,  and  the  arms  may  then  become 
fractured,  if  curved;  or,  if  straight,  may  prevent  the  rim  from 


236 

coming  inward,  and  S3  break  it.  Tn  mo"t  cases,  fracture 
occurs  from  the  mass  of  metal  in  the  boss.  Asa  single  instruct- 
live  example  out  of  many,  I  may  quote  that  of  a  pair  of 
2ft.  6  in.  pulleys,  fast  and  loose,  which  had  been  running  for 
several  years,  the  fast  pulley  had  a  boss  6  in.  in  diameter,  the 
loose  pulley  one  of  5  in.  only,  and  both  were  bored  to  3  in. 
By  the  accidental  falling  of  a  bar  of  iron,  both  were  broken. 
The  rim  of  the  fast  pulley  was  at  once  pulled  in,  while  the 
loose  pulley  remained  level  at  the  point  of  fracture.  This 
illustrates  the  presence  of  tension  in  the  rim,  due  to  the 
larger  bcss,  and  this  tension  had  been  present,  since  the  pulley 
was  made.  The  pulley  with  the  5  in.  boss  was  probably 
much  stronger  than  that  with  the  six  in.  boss.  Tn  fast  pul- 
leys, and  in  wheels  keyed  on,  the  necessary  strength  around 
the  key  way  may  be  obtained  by  the  use  of  key  way  bosses, 
without  increasing  the  entire  diameter  Where  large  bosses 
are  unavoidable,  as  in  some  deep,  double-armed  pulleys,  or 
in  spur  wheels  keyed  onto  large  shafts,  shrinkage  is  assisted 
by  opening  out  the  mold  around  the  bosses,  and  removing 
the  central  core,  thereby  accelerating  the  radiation  of  heat, 
and  further  by  cooling  them  with  water  from  a  swab  brush 
when  at  a  low  red  or  black  heat.  Many  a  casting  is  saved 
in  this  way  J  Vnother  method  is  to  split  the  boss  with  plates, 
and  bond  or  oolt  it  together  afterward.  When  casting  fly- 
wheels with  wrought-iron  arms,  the  rim  is  first  cast  around 
the  arms  and  allowed  to  cool  nearly  down  before  the  boss  is 
poured.  If  the  latter  were  cast  at  the  same  time  as  the  rim, 
it  would  set  first,  and,  by  preventing  the  arms  from  coming 
inward,  would  put  tension  upon  the  rim. 

Whe.tf  aggregations  of  metal  occur  in  castings,  they  may, 
if  the  castings  be  too  strong  to  fracture,  cause  an  evil  of 
a  secondary  character,  known  as  "  drawing;"  in  other  words, 
the  metal  is  put  into  a  condition  of  internal  stress,  and 
becomes  open  and  spongy  in  consequence.  "  Feeding  "  tends 
to  diminish  this  evil;  but  much  can  often  be  done  by  light- 
ening the  metal  with  cores,  chambering  out,  or  reducing  the 
metal  massed  in  certain  places  by  other  means.  There  is  a 
difference  in  the  behavior  of  cast-iron  and  of  gun  metal,  of 
which  advantage  may  be  taken  in  small,  light  castings. 
Designs  which  will  not  stand  in  cast-iron  or  steel  will  stand 
t\  gun  metal,  hence  the  latter  may  be  useful  in  cases  of  diffi- 
culty. 

Sharp  angles  very  often  lead  to  fracture.  When  brackets, 
ribs,  slugs,  etc.,  are  cast  on  work,  the  corners  should  never 
be  left  square  or  angular,  for,  if  there  be  much  disproportion 


237 

of  metal,  fracture   will  almost    certainly   commence  in  the 
angles. 

I  have  already  alluded  to  the  "  straining  "  which  large 
plated  and  heavy  castings  undergo,  so  that  the  sides  and 
faces  increase  in  dimensions,  becoming  more  or  less  rounded. 
The  main  reason  is,  I  think,  that  the  metal  round  the 
central  portions  does  not  cool  so  rapidly  as  that  at  the 
sides.  The  outsides  radiate  heat  quickly,  and  shrink  to 
their  full  extent;  but  the  middle  rib  or  ribs,  and  the  cen- 
tral portions  of  the  plate,  retain  their  heat  longer,  and 
hold  the  sides  in  a  condition  of  tension,  thus  forcing  them  to 
bulge  or  become  round.  When  the  central  portions  cool, 
the  outsides  are  too  rigid  to  yield  to  the  inward  pull.  This 
refers  to  framed  hollow  work.  When  plates  "  gather  "  or 
increase  in  thickness,  it  is  due  mainly  to  the  lifting  of  the 
cope,  from  insufficient  weighting.  When  a  cubical  mass  of 
metal  shows  no  shrinkage,  this  is  due  to  the  pressure  of  the 
entire  mass  compressing  the  sand  on  every  side. 

Briefly  stated,  then,  in  deciding  the  proper  contraction 
allowance  for  a  pattern,  I  should  take  into  consideration  its 
mass,  the  manner  in  which  it  is  molded  and  cast,  the  presence 
or  absence  of  cores,  and  the  nature  of  the  same,  its  general 
outline,  and  the  character  of  the  metal.  For  a  heavy  solid 
casting  in  iron,  I  should  allow  considerably  less  than  t!\e 
normal  contraction  for  iron  ;  for  a  similar  casting  in  stee], 
more  than  the  normal  contraction  for  steel ;  for  a  heavy 
casting  in  gun  metal,  less  than  the  normal  contraction  for 
gun  metal.  The  precise  allowance  in  any  case  must  be 
regulated  by  circumstances.  For  the  vertical  depth  of  a 
shallow  casting,  very  little  shrinkage,  if  any,  should  be 
allowed;  for  a  deep  casting,  the  full  amount.  Then,  again, 
a  mold,  with  dry  sand  cores  of  moderate  or  large  size,  will 
not  allow  the  casting  to  shrink  so  much  as  if  the  cores  were 
of  green  sand,  or  were  altogether  absent.  For  hard  and 
chilled  iron,  the  shrinkage  will  be  at  its  maximum  ;  for 
strong  mottled  iron,  at  its  maximum  ;  and  for  common  gray 
metal,  at  about  the  average. 

FLEXIBLE  GLASS. 

An  article  called  flexible  glass  is  now  made  by  soaking 
paper  of  proper  thickness  in  copal  varnish,  thus  making  it 
transparent,  polishing  it  when  dry,  and  rubbing  it  with  pumice 
stone.  A  layer  of  soluble  glass  is  then  applied  and  rubbed 
with  salt.  The  surface  thus  produced  is  said  to  be  as  perfect 
as  ordinary  srlass 


SOME  ELECTRIC  LIGHT  FIGURES. 

Now  that  modern  improvements  in  the  methods  of  dis- 
tributing electricity  for  incandescent  lighting  have  rendered  it 
practicable  to  establish  and  maintain  central  station  plants 
at  a  profit,  even  in  towns  of  not  more  than  4,000  inhabitants^ 
it  has  become  possible  to  ascertain,  with  some  approach  to 
accuracy,  the  dimensions  of  the  field  which  is  open  to  be  oc- 
cupied by  this  incomparable  illuminant. 

Experience  shows,  that,  when  house-to-house  lighting  has 
been  thoroughly  worked  up  in  any  town,  the  capacity  of  the 
central  station  plant  will  need  to  be  equal  to  an  average  of 
about  one-sixteenth  candle-power  lamp  for  each  inhabitant. 

According  to  the  census  of  1880  of  the  50,000,000 
inhabitants  of  the  United  States,  13,000,000,  or  26  percent., 
resided  in  580  towns  and  cities  having  a  population  in  excess 
of  4,000  each. 

At  the  normal  rate  of  increase,  we  shall  have,  in  five  years 
from  the  present  writing,  a  population  of  nearly  70,000,000, 
of  whom  some  18,000,000  will  be  gathered  within  the  limits 
of  towns  of  4,000  inhabitants,  and  upward.  Each  of  these 
individuals  will  represent  one  incandescent  lamp,  and  the 
necessary  power  for  operating  the  same.  Even  after  deduct- 
ing the  lamps  which  have  already  been  installed,  there  will  be 
required  a  total  output  of  more  than  u,oco  lamps,  and  over 
I,ooo  horse-power  each  of  steam  engines,  boilers  and 
dynamos,  every  working  day  for  the  next  five  years,  to 
supply  the  demand  which,  from  all  present  appearances,  will 
inevitably  arise.  This  is  entirely  aside  from  the  additional 
number  of  lamps  which  will  be  required  for  renewals — itself 
an  enormous  item.  The  change  from  gas  to  electricity, 
which  is  now  going  on  in  connection  with  domestic  lighting, 
will  be  not  a  little  accelerated  by  the  action  of  the  gas 
companies,  who  are  everywhere  evincing  an  increasing  dis- 
position to  take  up  electric  lighting  themselves ;  and  a  very 
sagacious  policy  it  is  too,  in  view  of  the  present  outlook  for 
gas  illumination. 

TO  CLEAN  RUSTY  STEEL. 

Mix  ten  parts  of  tin  putty,  eight  parts  of  prepared  buck's 
horn,  and  twenty-five  parts  of  spirit  of  wine  to  a  paste. 
Cleanse  the  steel  with  this  preparation,  a.  d  finally  rub  off 
with  soft  blotting  paper. 


239 
HINTS  ON  PATTERN-MAKING. 

The  pattern  shop  is  one  of  the  most  important  depart- 
ments in  a  plant  for  the  manufacture  of  machinery.  It  is 
here  that  the  plans  of  the  mechanical  engineer  are  first 
developed,  and  upon  the  skillful  manner  in  w'lich  the  pat- 
terns are  constructed  and  those  plans  faithfully  carried  out, 
depends  much  of  the  future  success  in  the  manufacture  of  the 
machine.  The  skillful  pattern-maker,  by  accurate  calcula- 
tions for  shrinkage,  finishing  and  the  contingencies  of  the 
foundry,  may  save  a  great  amount  of  labor  and  annoyance  in 
the  machine  shop.  It  is  unreasonable  to  expect  perfect  cast- 
ings from  imperfect  patterns,  and  the  molder  is  often  blamed 
for  imperfections  of  the  castings  when  the  fault  may  be  traced 
to  an  imperfect  pattern.  Holders  as  a  class  have  sins 
enough  of  their  own  to  answer  for  without  the  addition  of 
the  sins  of  the  pattern-maker.  Patterns  are  as  a  rule  neces- 
sarily expensive,  and  should  be  carefully  constructed,  so  that 
they  will  retain  their  shape  and  proportions  for  future  use, 
and  to  this  end  the  selection  of  materials  and  the  manner  of 
joining  the  several  parts  together  becomes  an  important  item. 
For  all  ordinary  purposes,  especially  for  patterns  of  consider- 
able size,  good,  clear,  well-seasoned  white  pine  is  the  best, 
and  to  obtain  the  best  results  it  should  be  seasoned  in  the 
open  air  in  the  natural  way.  The  sap  of  all  the  woods  con- 
tains a  k.rge  percentage  of  water,  and  to  get  rid  of 
this  is  the  object  in  seasoning.  Pine  wood,  besides 
water,  'contains  a  large  percentage  of  turpentine  in 
the  sap,  and  in  seasoning  it,  it  is  desirable  to  retain 
as  much  of  this  as  possible,  as  it  dries  to  a  hard  substance 
when  seasoned  in  the  open  air,  and  helps  in  a  measure  to  fill 
up  the  pores  of  the  wood,  and  renders  it  close  and  more 
impervious  to  water,  and  less  liable  to  be  affected  by  damp- 
ness. Kiln-dried  lumber,  although  extensively  used  at  the 
present  time,  is  not  as  good  for  this  purpose.  The  heat  and 
moisture  used  for  this  purpose  expels,  not  only  the  water, 
but  other  ingredients,  which  leaves  the  grain  open  and  brash, 
and  patterns  made  from  such  materials  are  more  liable  to 
absorb  dampness  and  warp  than  otherwise.  In  constructing 
patterns,  especially  those  of  considerable  size,  it  is  cus- 
tomary to  build  them  up  of  several  pieces  glued  together; 
this  makes  more  reliable  work,  provided  good  glue  is  used 
and  proper  care  manifested  in  the  manner  of  putting 
them  together.  No  two  pieces  should  be  glued  together 
with  grain  crossing  at  right  angles,  for,  no  matter  how  dry 
the  lumber  may  be,  there  will  always  be  soma  shrinkage, 


240 

and,  as  lumber  shrinks,  almost  entirely,  in  its  transverse  sec- 
tion, it  is  sure  to  warp,  unless  the  glue  gives  way  so  as  to 
allow  each  part  to  shrink  in  its  natural  direction.  In  either 
case  the  pattern  will  be  unfit  for  further  use  until  it  is 
repaired.  It  is  not  good  practice  either,  to  glue  up  stuff  for 
patterns  with  the  grain  of  each  piece  running  parallel  with 
the  other,  as  such  patterns  are  deficient  in  strength,  and  are 
liable  to  split.  The  most  practical  way  is  to  arrange  the 
several  pieces  so  that,  when  put  together,  the  grain  will  run 
diagonally  across  each  piece,  at  an  angle  of  about  twenty- 
five  or  thirty  degrees.  Pattern  stuff  prepared  in  this  man- 
ner will  have  sufficient  strength  to  prevent  splitting  by  use 
and  handling,  and  the  tendency  for  warping  will,  to  a  great 
extent,  be  avoided.  In  building  up  circles,  the  cants  should 
be  short,  and  cut  lengthwise  of  the  grain  as  far  as  possible, 
so  that  the  grain  of  each  course  as  it  is  laid  together  to 
break  points,  may  cross  each  other  diagonally.  It  is  cus- 
tomary with  some  pattern-makers  to  use  nails  or  birds  in 
each  course  as  it  is  laid  up,  but  pegs  made  of  maple 
or  hickory  are  much  better,  and,  when  the  stuff  is  suffi- 
ciently thin  to  admit  of  it,  the  common  pegs  used  in  shoe 
shops  are  very  cheap  and  convenient.  The  advantage  of 
using  pegs  instead  of  brads  or  nails  i-,  that,  being  driven 
in  glue,  they  hold  better,  and  the  cants  are  not  as  liable  to 
spring  apart  when  exposed  to  the  warm,  damp  sand  in  the 
foundry;  besides,  they  never  give  the  workman  any  trouble 
when  turning  it;  and  experience  has  demonstrated  that  pat- 
terns put  together  in  this  manner  are  much  more  durable 
than  otherwise.  Some  pattern-makers  use  but  little  judg- 
ment in  the  use  of  glue,  and  seem  to  have  an  idea  that  the 
more  glue  they  can  get  between  two  surfaces  the  better;  yet, 
every  experienced  mechanic  knows  that  exactly  the  reverse 
is  the  case.  With  a  good  joint  and  clear,  fresh,  thin  glue, 
the  least  that  is  retained  between  the  two  surfaces  the  bet- 
ter and  stronger  will  be  the  joint.  In  hot  weather  glue  soon 
sours,  turns  black  and  becomes  rancid;  when  in  this  condi- 
tion, its  strength  is  impaired  and  it  is  unfit  for  use.  Alco- 
hol mixed  with  it  will  prevent  souring,  but,  as  soon  as  it  is 
healed  up,  the  alcohol  evaporates,  and  its  effects  are  lost. 
The  most  effective  preventive  is  sulphuric  acid,  but  the 
acid  should  not  be  applied  clear.  For  an  ordinary  glue-pot 
about  fifteen  drops  of  the  acid  mixed  writh  a  couple  of 
spoonfuls  of  water  may  be  applied;  while  this  in  no  way 
impairs  the  strength  of  the  glue,  it  will  effectually  prevent 
souring,  and  keep  it  fresh  and  clear. 

For  small  gear  patterns  that  are  to  be  in  constant  use,  cut 


patterns  of  iron  or  brass  are  no  doubt  the  best  and  cheapest 
in  the  end;  but,  if  wood  patterns  are  required,  they  should  be 
made  of  some  harder  wood  than  pine  ;  mahogany  or  cherry 
is  considered  the  best  for  such  work.  After  the  hub  is  turned 
to  the  proper  size  and  width  of  face,  the  blanks  for  the  teeth 
may  be  glued  on  and  dressed  in  their  places..  With  large, 
wide-faced  gears,  it  is  not  convenient  to  do  so  ;  the  blanks 
for  the  cogs  are  usually  glued  to  dovetailed  slips,  or  the 
dovetailed  formed  on  the  under  side  of  the  blank  so  thatr 
when  fitted  to  the  rim,  or  dressed  off,  and  laid  out,  they  max 
be  removed  for  the  convenience  of  finish  ing  them.  The 
dove-tails  should  be  a  perfect  fit,  and  the  blank  well  fitted 
to  the  rim;  otherwise  they  will  vary  the  pitch  when  dressed 
and  replaced  again.  In  constructing  patterns  for  heavy 
castings,  such  as  lathe  and  engine  beds,  the  careful  and  evei? 
distribution  of  metal  in  each  part  is  an  important  considers 
tion,  and,  in  order  to  give  some  particular  part  the  requisite 
strength  to  withstand  a  heavy  strain,  it  is  sometimes  necessary 
to  put  more  metal  in  some  other  part  where  it  is  not  needed 
in  order  to  prevent  the  casting  from  being  distorted  in  shape 
or  cracked  by  the  unequal  construction  caused  by  one  part 
cooling  faster  than  another.  With  the  framework  for  lighter 
machinery  the  same  allowanc  *  for  shrinkage  must  be  provided 
for.  But  where  a  frame  is  composed  of  several  parts,  some 
of  which  are  much  lighter  than  others  and  yet  it  is  necessary 
that  the  whole  should  be  cast  together,  it  is  well  to  make 
the  lighter  portions  in  curves  as  far  as  the  nature  of  the  work 
will  permit.  Shurp  edges  and  square  corners  should  also  be 
avoided  as  far  as  possible.  A  small  cove  in  each  corner  will 
add  much  to  the  convenience  of  molding,  besides  adding  to 
the  strength  of  the  casting  and  insure  it  against  cracks,  which 
are  liable  to  open  at  these  points  by  shrinkage  in  cooling. 

The  pattern-maker  should  also  exercise  good  judgment 
in  making  provision  for  withdrawing  the  pattern  from  the 
sand;  but,  as  no  two  patterns  are  just  alike  in  this  respect,  no 
definite  rule  can  be  followed.  In  intricate  patterns,  which 
require  considerable  skill  and  care  on  the  part  of  the  molder 
in  withdrawing  them  from  the  sand,  if  the  nature  of  the 
work  will  admit  of  it,  considerable  more  draft  should  be 
allowed  for  this  reason.  But  plain  patterns  may  be  nearly 
straight,  provided  their  surface  is  perfectly  smooth.  For 
much  draft,  especially  with  gearing,  is  very  objectionable, 
for  it  is  impossible  for  such  gearing  to  run  together 
accurately,  and  bear  the  whole  length  of  the  tooth  or 
cog,  unless  they  are  either  chipped  and  filled,  «Dr  planed 
straight.  If  gear  patterns  are  made  accurate  and  true, 


and  the  face  of  the  cogs  perfectly  smooth,  there  will  be 
no  difficulty  in  molding  them  if  they  are  nearly  or  quite 
straight.  All  patterns  before  being  used  should  be  well 
covered  with  at  least  two  coats  of  pure  shellac  varnish. 
After  applying  the  first  coat,  and  when  it  is  perfectly  dry, 
the  surface  should  be  well  rubbed  down  with  fine  sandpaper, 
and  all  imperfections,  such  as  nail  holes  and  sharp  corners, 
not  already  provided  for,  should  be  carefully  filled  with  bees- 
wax and  rubbed  off  smooth  before  the  second  coat  of  var- 
nish is  applied.  After  a  pattern  has  once  been  used,  it  is 
good  practice  to  again  rub  it  off  with  very  fine  sandpaper, 
and  apply  another  coat  of  varnish.  Many  well-made  pat- 
terns are  ruined  in  the  foundry  by  not  being  provided  with 
the  proper  facilities  for  rapping  and  drawing.  The  molder 
Jnust  have  some  means  for  attaching  his  appliances  for  lift- 
ing it  out,  and,  if  suitable  provision  is  not  made  for  this  pur- 
pose, he  will  screw  his  lifter  in  any  part  of  the  pattern  that 
is  most  convenient,  and  the  chances  are,  that  it  will  split  the 
first  time  it  is  used,  or  badly  marred  up.  Iron  plates  should 
be  let  into  all  patterns  with  holes  threaded  to  suit  his  lifters, 
and  well  secured  either  by  screws  or  rivets,  and,  if  a  sufficient 
number  are  attached,  the  molder  will  respect  the  pattern  and 
use  them.  Wood  patterns  should  never  be  allowed  to 
remain  in  the  foundry;  as  soon  as  they  are  used,  they  should 
be  taken  to  the  pattern-room,  brushed  off  and  placed  in  such 
a*  position  for  future  use  that  they  will  not  become  warped 
or  sprung. 

ELECTRIC  HAND  LANTERN. 

A  German  patent  has  been  granted  to  A.  Friedlander 
for  an  electric  hand  lantern.  This  consists  of  a  box  of  hard 
rubber  carrying  a  small  three-candle  power  incandescent 
light,  together  with  a  reflector  and  glass  protector.  The 
elements  in  the  box,  carbon  and  zinc,  produce  the  current 
necessary  to  feed  the  light.  The  box  is  divided  into  five 
compartments  holding  the  liquid,  and  the  electrodes  are 
placed  in  such  position  that  r,o  decomposition  occurs  when 
the  lantern  is  not  in  uce,  The  <  irciiit  is  closed  when  the 
electrodes  are  dipped  in  the  liquid;  the  current  is  stronger 
and  the  li^ht  brighter  if  tlvj  electrodes  are  dipped  deeper  in 
the  liquid  ;  this  depth  ard  consequently  the  brightness  of  the 
light  can  be  regulated  by  means  of  a  button  on  the  outside. 
The  liquid  is  a  combined  solution  of  chloride  of  zinc,  bichro- 
mate of  soda  in  wa'er  and  acid,  and  the  lantern  can  hold  a 
sufficient  supply  of  th  s  solution  t^  last  for  about  three  hours. 


243 

TABLES  OF  GEARS    FOR   CUTTING   STANDARD 
SCREW-THREADS. 

INTRODUCTION. 

It  may,  perhaps,  be  necessary  to  state  that  these  tables 
are  the  fruit  of  much  experience,  and  a  deep-seated  convic- 
tion that  their  want  is  sorely  felt  by  many.  Notwithstanding 
the  vast  improvements  of  modern  screw-cutting  machinery, 
much  time  is  still  wasted  by  the  most  experienced  workmen 
in  endeavoring  to  find  wheels  to  but  any  particular  pitch  o, 
screw,  or  broken  number,  in  consequence  of  the  various 
changes  to  be  obtained  from  the  usual  set  of  screw-cutting 
wheels,  most  of  which  begin  with  a  2O-teeth,  25,  30,  35,  40, 

45>  5°»  55»  6o»  65»  7°»  75 »  8o»  85>  9°>  95>  I00>  no,  I20>  i3°» 
140  and  150.  This  may  be  considered  a  full  set,  inasmuch  as 
any  screw  may  be  cut  with  it  Supposing  the  ao-wheel  to 
be  put  on  the  mandrel,  for  single  changes,  without  the  pinion, 
the  first  figure  up  to  95  will  give  the  number  of  threads  to 
the  inch.  A  20  and  A  25  will  cut  2^  ;  20  and  30,  3  to  the 
inch,  and  so  on  in  like  ratio.  When  three  figures  are  on  the 
wheels,  however,  the  first  two  will  indicate  the  number  to 
the  inch  ;  as,  20  and  100  will  cut  10  ;  20  and  no  will  cut  n; 
etc.  For  many  common  numbers  this  will  save  the  trouble 
of  looking  to  the  tables,  if  a  f£,  ^,  or  other  coarse  pitch. 
If  the  book  be  referred  to  for  the  decimal  of  the  ratios 
required,  against  it  will  be  found  the  wheels  that  will  cat  it. 
If  the  number  be  required  to  the  foot,  then  multiply  by  tv/elve. 

These  tables  are  calculated  on  the  assumption  that  a  pin- 
ion  of  twenty  teeth  is  used,  and  a  driving-screw  of  two 
threads  to  the  inch. 

Wheels,  when  affixed  to  the  mandrel,  are  r  Olcu  maadrel- 
wheels  ;  those  on  the  screw,  screw-wheels  ;  ar  d  those  inter- 
vening, intermediate-wheels.  When  the  may  drel  and  screw- 
wheels  are  connected  by  one  or  more  whe  .Is  directly,  they 
are  termed  simple  wheels.  When  attach?  (  by  means  of  a 
pinion  joined  to  the  intermediate  wheeJ  '  =^ey  are  calledcom* 
pound  wheels. 

io.  I,  is  a  table  of  sim^i«  wneels.  The  mandrel- wheels 
are  in  the  first  perpendicular  column;  and  the  screw-wheels 
in  the  top  horizontal  column.  In  the  spaces  where  the  per- 
pendicular intersects  the  horizontal,  will  be  found  the  pitch  of 
the  thread  which  any  two  wheels  will  cut. 

The  remaining  tables  are  of  compound  wheels.  The 
mandrel-wheels  will  be  found  in  the  first  perpendicular  column, 
the  intermediate-wheels  in  the  top  horizontal  column,  and 
the  screw-wheels  in  the  bottom  column.  The  pitch  of  thread 


244 

to  be  cut  having  been  found  in  the  tables,  on  the  left  hand 
the  mandrel- wheel  will  be  found,  on  the  top  the  intermediate 
wheel,  and  at  the  bottom  the  screw-wheel. 

All  lathes  have  not  a  twenty-teeth  pinion,  in  which  case, 
the  following  rule  will  be  of  use  as  applying  to  any  other 
pinion : 

Multiply  the  pitch  of  thread  intended  to  be  cut,  by  the 
new  pinion,  and  divide  by  twenty.  Find  the  wheels  in  the 
tables  corresponding  with  the  quotient,  and  use  the  new  pin- 
ion instead  of  the  twenty. 

In  some  lathes  the  mandrel-wheel  is  a  fixture.  In  these 
instances,  suppose  the  mandrel-wheel  to  be  the  pinion,  and 
attach  the  mandrel-wheel  found  in  the  table  to  the  interme- 
diate-wheel. 

To  ascertain  the  ratio  of  any  series  of  wheels,  multiply 
the  whole  of  the  driven  wheels  together,  which  will  give  the 
total  number  of  teeth  in  the  series.  Then  divide  the  result 
by  the  driving  wheels  multiplied  into  each  other.  The  quo- 
tient will  be  the  number  of  times  the  first  wheel  will  revolve 
to  the  last.  Suppose  a  wheel  of  twentv  teeth  to  be  driving 
a.  wheel  of  100  teeth,  to  which  is  attached  a  wheel  of  thirty 
teeth  driving  a  wheel  of  150  teeth,  and  the  ratio  be  required — 
loo  X  150 

=25  revolutions. 

20  X    30 

To  find  the  number  of  threads  a  set  of  wheels  will  cut,  multiply  the 
ratio  of  the  wheels  by  the  pitch  of  the  driving-screw. 

To  cut  double  or  more  threads,  divide  the  mandrel-wheel  in  as 
many  parts  as  you  require  threads,  and,  as  you  cut  the  screw,  shift  the 
mandrel-wheel  a  division,  while  the  screw-wheel  remains  stationary. 
This  plan  will  insure  equal  division  and  regularity  of  cutting.  In  all 
lathes  where  the  leading  screw  is  two  to  the  inch,  and  an  equal  number 
of  threads  being  cut,  if  the  saddled  clutch  be  thrown  out  of  gear,  it  will 
always  fall  into  the  right  place.  If  an  odd  number  of  threads  are  being 
cut,  it  will  fall  right  every  other  one.  By  attending  to  this  rule,  run- 
ning the  lathe  backward  will  be  avoided,  and  a  screw  cut  in  about  half 
the  time. 

A  difficulty  frequently  arises  in  finding  the  number  of  threads  to  the 
li.ch  or  foot  when  a  particular  pitch  or  fractional  number  has  to  be 
matched.  This  can  easily  be  ascertained  J)y  measuring  onward,  for,  if 
it  do  not  come  right  in  one  inch,  notice  how  many  there  are  between 
any  division  of  rule.  In  measuring  a  screw,  you  discover  there  are 
twenty-eight  threads  in  three  inches.  Consequently,  if  twenty-eight  be 
divided  by  three,  it  gives  9. 333  as  the  pitch.  Against  that  number  in 
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in  twelve  inches:  as,  1.615  in-  pitch  into  12  in.  is  7.384101116  foot.  If 
divided  by  twelve,  we  have  the  dec.  .615,  against  which  in  th<*  table 
will  be  found  the  wheels. 


245 


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265 


TABLE  FOR  MAKING  THE  UNIVERSAL  TAPS, 
WITH  THE  MOST  SUITABLE  PROPORTIONS 
REQUISITE  FOR  GOOD  WORKING  TAPS 
USED  BY  HAND. 

From  /4  to  j^-  the  head  is  turned  the  same  sire  as  the 
screw;  the  ^j,  and  all  above,  to  pass  through  the  holes 
screwed.  As  the  same  table  shows  the  size  of  tap  and  bol^- 
torn  of  screw,  the  workman  will  be  enabled  to  make  the 
tapping  holes  a  size  that  will  insure  a  full  thread.  The  bat- 
torn  of  screw  will  give  the  size  for  drills,  bits,  etc. 


rt                S  J^        :     ^     :  § 

- 

o 

Wheels  fcj  cutting 
the  screws. 

«*-                           r£      t/)            |        'O              £o 

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20 

90 

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; 

20     70 

I,H            «#;.         ^      7        1    4X1               '    ' 

.....      00 

266 


TABLE  FOR  MAKING  THE  UNIVERSAL  TAPS  -  (Continued.) 


£ 

T3     <L>              i           CH 

'  <3  "o                   rt   -     "  ?              . 

«  2            ^     i    «       .    o 

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Si 

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5 

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10 

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3 

K      40 

70 

UNIVERSAL  GAS-PIPE  THREADS. 

WHEELS  FOR  CUTTING,  ETC. 


DIAMETER. 

Man- 
drel. 

Interme- 
diate. 

Pinion. 

Screw. 

Pitch. 

I#»  find  all  above 
i  .  .  . 

85 
20 

So 

20 

120 
IAO 

11.294 

$£  

20 

IAO 

id. 

^o 

6c 

20 

8c 

18  412 

Small  brass  tube  .  . 

3o 

60 

20 

120 

24. 

HOW  PUMICE  STONE   IS  MADE. 
Pumice  stone  is  now  prepared  by  molding  and  baking  a 
mixture  of  white  feldspar  and  fire-clay.     This  product  is  said 
to   have  superseded   the    natural    stone    in    Germany    and 
Austria. 


26; 
NOTES  ON  THE  WORKING  OF  STEEL. 

1.  Good  soft  heat  is  safe  to  use  if  steel  be  immediately 
and  thoroughly  worked. 

It  is  a  fact  that  good  steel  will  endure  more  pounding  than 
any  iron. 

2.  If  steel  be  left  long  in  the  fire  it  will  lose  its  steely  na- 
ture and  grain,  and  partake  of  the  nature  of  cast  iron. 

Steel  should  never  be  kept  hot  any  longer  than  is  necessary 
to  the  work  to  be  done. 

3.  Steel  is  entirely  mercurial  under  the  action  of  heat, 
and  a  careful  study  of  the  tables  will  show  that  there  must  of 
necessity  be  an  injurious  internal  strain  created,  whenever 
two  or  more  parts  of  the  same  piece  are  subjected  to  dif- 
ferent temperatures. 

4.  It  follows  that  when  steel  has  been   subjected  to  heat 
not  absolutely  uniform  over  the  whole  mass,  careful  anneal- 
ing should  be  resorted  to. 

5".  As  the  change  of  volume  due  to  a  degree  of  heat  in- 
creases directly  and  rapidly  with  the  quantity  of  carbon 
present,  therefore  high  steel  is  more  liable  to  dangerous  in- 
ternal strain  than  low  steel,  and  great  care  should  be  exer- 
cised in  the  use  of  high  steel. 

6.  Hot  steel  should  always  be  put  in  a  perfectly  dry  jilace 
of  even  temperature  while  cooling.     A  wet  place  in  the  floor 
might  be  sufficient  to  cause  serious  injury. 

7.  Never  let  any  one  fool  you  with  the  statement  that  his 
iteel  possesses  a  peculiar  property  which  enables  it   to  be 
"  restored  "  after  being  "  burned;"  no  more  should  you  waste 
any  money  on  nostrums  for  restoring  burned  steel. 

We  have  shown  how  to  restore  "  overheated  "  steel. 

For  "  burned  "  steel,  which  is  oxidized  steel,  there  is  only 
one  way  of  restoration,  and  that  is  through  the  knobbling  fire 
or  the  blast  furnace. 

"  Overheating  "  and  "  restoring  "  should  only  be  allowable 
for  purposes  of  experiment.  The  process  is  one  of  disintegra- 
tion, and  is  always  injurious. 

8.  Be  careful  not  to  overdo  the  annealing  process;  if  car- 
ried too  far  it  does  great  harm,  and  it  is  one  of  the  commonest 
modes  of  destruction  which  the  steelmaker  meets  in  his  daily 
troubles. 

It  is  hard  to  induce  the  average  worker  in  steel  to  believe 
that  very  little  annealing  is  necessary,  and  that  a  very  little 
is  really  more  efficacious  than  a  great  deal. 


268 

WEIGHT  AND  NUMBER  OF  SQUARE  NUTS  IN  A 
BOX  OR  KEG  OF  200  POUNDS. 


Width. 

Thick- 
ness. 

Hole. 

Size  of 
Bolt. 

No.  in 
200  Ibs. 

Weight 
of  Nut. 

yz 

X 

7-3^ 

X 

14,844 

Ibs. 

e/ 

5-16 

Q-^2 

7,'88o 

V 

11-^2 

•M? 

4,440 

*A 

7*16 

o** 

I  3-32 

7-16 

2,772 

s° 

/ 

7-16 

/  * 

5  /  d 

2,45° 



1 

i/ 

7-16 

c    /* 

1,816 

Jl/ 

y 

/ 

Q-  16 

1,^00 

*1A 

X 

79-i6 

|       c/ 

13  j 
M74 

•*7 

*X 

H 

9-16 

j-     /8 

898 

•23 

\$ 

X 

21-32 

I   v 

662 

•3 

H 

21-32 

i   M 

538 

•37 

1$ 

7A 

25-32 

1 

392 

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7A 

25-32 

C      /» 

326 

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1$. 

i 

X 

3<>4 

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2 

i 

y% 

r* 

224 

.89 

2 

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15-16 

214 

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15-16 

r  1% 

152 

1-32 

2X 

\% 

1-16 

1     I/ 

143 

1.4 

9.Yz 

l% 

1-16 

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108 

1.85 

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ift 

3-16 

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2.41 

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3 

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2    II-I6 

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3 

14 

AMOUNT      OF      HEAT      REQUIRED     TO      MELT 
WROUGHT  IRON. 

The  temperature  necessary  to  melt  wrought  iron  lies 
between  4,000°  and  5,000°  F.,  and  ev«m  at  that  tremendous 
heat,  wrought  iron  is  only  rendered  fluid  by  the  addition  of  a 
small  amount  of  aluminum. 


269 

WEIGHT  AND  NUMBER  OF  HEXAGON  NUTS 
A  KEG  OR  BOX  OF  200  POUNDS. 


Width. 

Thick- 
ness. 

Hole. 

Size  of 
Bolt. 

No.  in 
200  Ibs. 

Weight 

of  Nut. 

X 

X 

7-32 

X 

17,332 

IbflL 

5^ 

C-  16 

Q-^2 

K-  16 

8,964 

v 

li 

y 

5,016 

7A 

7    /• 
7-16 

I  V^2 

7-16 

2,988 

7A 

7-16 

1 

2,674 

if  9 

/! 

'      - 
7-16 

c 

'    4T 

2,160 

>0 

I/. 

9-16 

Q-l6 

I.44.C 

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9-16 

j  ' 

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9-16 

\ 

920 

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21-32 
21-32 

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752 
510 

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25-32 

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428 

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336 

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15-16 

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211 

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Xs 

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1-16 

X 

159 

1.26 

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3-16 

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119 

1.68 

5-16 

l/z 

88 

2.27 

3 

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7-16 

y% 

69 

2.9 

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9-l6 

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56 

3-6 

3K 

2 

11-16 

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I!5_ 

HOW  TO  PREVENT  GEAR  TEETH   FROM  BREAKING. 

Gear  teeth  generally  have  one  corner  broken  off  first,  after 
which  they  rapidly  go  to  pieces.  This  may  be  avoided  and 
the  teeth  made  much  stronger  by  thinning  down  the  edges 
with  a  file,  thereby  bringing  the  whole  strain  along  the  centre 
of  the  tooth.  jear  teeth  fixed  this  way  will  not  break  unless 
the  strain  be  sufficient  to  br-sak  off  the  whole  tooth. 


2JO 

NUMBER  OF  LIGHTS   OF  WINDOW  GLASS  IN  A 
BOX  OF  50  FEET. 


Size. 

No. 
Lights. 

Size. 

No. 
Lights. 

Size. 

No. 

Lights. 

6x  8 

I50 

28 

16 

5° 

5 

7x  9 
Sxio 

90 

30 
18x22 

18 

30x38 
40 

I 

II 

82 

24 

17 

42 

6 

12 

75 

26 

16 

44 

6 

13 

69 

28 

H 

46 

5 

14 

64 

3° 

48 

5 

9x12 

67 

32 

13 

50 

5 

13 

62 

20x26 

H 

52 

5 

H 

57 

28 

13 

54 

4 

15 

53 

30 

12 

32x40 

6 

10x13 

56 

32 

II 

42 

H 

52 

34 

II 

32x44 

5 

15 

48 

36 

10 

46 

s 

16 

45 

22x28 

12 

48 

11x14 

47 

30 

II 

5° 

5 

15 

44 

32 

10 

52 

4 

16 

41 

34 

10 

54 

4 

18 

39 

36 

9 

56 

4 

12x15 

40 

38 

9 

34x44 

5 

16 

38 

24x30 

10 

46 

5 

18 

34 

32 

10 

48 

5 

20 

3° 

24x34 

9 

5° 

4 

13x16 

35 

36 

9 

52 

4 

18 

31 

38 

8 

54 

4 

20 

28 

40 

8 

56 

4 

22 
14X18 

25 
29 

26x32 
.34 

I 

£ 

4 
4 

20 

26 

8 

36x46 

4 

22 

24 

38 

7 

48 

4 

24 

22 

40 

7 

50 

4 

ISXI8 

27 

42 

7 

52 

4 

2O 

24 

44 

6 

54 

4 

12 

22 

28x36 

7 

56 

4 

24 
26 

20 
19 

38 
40 

7 

7 

58 
36x60 

3 
3 

16x20 

23 

42 

6 

62 

3 

22 

21 

44 

6 

64 

3 

24 

19 

^46 

6 

38x46 

4 

26 

17 

48 

5 

48 

4 

NUMBER  OF   LIGHTS   OF  WINDOW  GLASS  IN  A 
BOX  OF  50  FEET.-Continued. 


Size. 

No. 
Lights. 

Size. 

No. 
Lights. 

Size. 

Na 
Lights 

5° 

4 

60 

3 

66 

3 

52 

4 

40x62 

3 

68 

54 

4 

64 

3 

70 

a 

Co 

3 

66 

3 

44*54 

3 

58 

3 

40x68 

3 

5S 

3 

60 

62 

3 

3 

70 
42x50 

3 
3 

II 

3 
3 

64 

3 

52 

3 

62 

3 

66 

3 

54 

3 

64 

3 

40x48 

4 

56 

3 

66 

2 

50 

4 

58 

3 

68 

2 

52 

3 

60 

3 

70 

2 

54 

3 

62 

3 

72 

2 

56 

3 

64 

3 

COMBUSTIBILITY  OF  IRON  PROVED. 

Combustion  is  not  generally  considered  one  of  the  prop- 
erties of  iron,  yet  that  metal  will,  under  proper  conditions, 
burn  readily.  The  late  Professor  Magnus,  of  Berlin,  Ger» 
many,  devised  the  following  method  of  showing  the  combus- 
tibility of  iron  :  A  mass  of  iron  filings  is  approached  by  a 
magnet  of  considerable  power,  and  a  quantity  thereof  is  per- 
mitted to  adhere  to  it.  This  loose,  spongy  tuft  of  iron  pow- 
der contains  a  large  quantity  of  air  imprisoned  between  its 
particles,  and  is,  therefore,  and  because  of  its  extremely  com- 
minuted condition,  well  adapted  to  manifest  its  combustibil- 
ity. The  flame  of  an  ordinary  spirit  lamp  or  Bunsen  burner 
readily  sets  fire  to  the  finely  divided  iron,  which  continues  to 
burn  brilliantly  and  freely.  By  waving  the  magnet  to  and 
fro,  the  showers  of  sparks  sent  off  produce  a  striking  and 
brilliant  effect. 

The  assertion  that  iron  is  more  combustible  than  gun- 
powder, has  its  origin  in  the  following  experiment,  which  is 
also  a  very  striking  one:  A  little  alcohol  is  poured  into  a 
saucer  and  ignited.  A  mixture  of  gunpowder  and  iron  filings 
is  allowed  to  fall  in  small  quantities  at  a  time  into  the  flame 
of  the  burning  alcohol,  when  it  will  be  observed  that  the  iron 
will  take  fire  in  its  passage  through  the  flame,  while  the  gun- 


272 

powder  wPl  fall  through  it  and  collect  beneath  the  liquid 
alcohol  below  unconsumed.  This,  however,  is  a  scientific 
trick,  and  the  experiment  hardly  justifies  the  sweeping  asser- 
tion that  iron  is  more  combustible  than  gunpowder.  The 
ignition  of  the  iron  under  the  foregoing  circumstances  is  clue 
to  the  fact  that  the  metal  particle-  being  admirable  con- 
ductors of  heat,  are  able  to  absorb  *,<_"  x-nt  heat  in  their 
passage  through  the  flame  —  brief  as  this  K.  -mid  they  are 
consequently  raised  to  the  ignition  point.  The  ±  'nicies  of 
the  gunpowder,  however,  are  very  poor  conductors  ^.  '-eat, 
comparatively  speaking,  and,  during  the  exceedingly  brief 
time  consumed  in  their  passage  through  the  flame,  they  do 
not  become  heated  appreciably,  or  certainly  not  to  their  point 
of  ignition.  Under  ordinary  circumstances,  gunpowder  is 
vastly  more  inflammable  than  iron. 

Another  method  of  exhibiting  the  combustibility  of  iron, 
which  would  appear  to  justify  the  assert  ion  that  it  is  really 
more  combustible  than  gunpowder,  is  the  following:  Place 
in  a  refractory  tube  of  Bohemian  glass  a  quantity  of 
dry,  freshly-precipitated  ferric  exide.  Heat  this  oxide  to 
bright  redness,  and  pass  a  current  of  hydrogen  through  the 
tube.  The  hydrogen  will  deprive  the  oxide  of  its  oxygen, 
and  reduce  the  mass  to  the  metallic  state.  If,  when  the 
reduction  appears  to  be  finished,  the  tube  is  removed  frcin 
the  flame,  and  its  contents  permitted  to  fall  out  into  th~  air 
it  will  take  fire  spontaneously  and  burn  to  oxide  again. 
This  experiment  indicates  that  pure  iron,  in  a  state  of  the  ex- 
tremest  subdivision,  is  one  of  the  most  combustible  sub- 
stances known  —  more  so,  even,  than  gunpowder  and  other 
explosive  substances  which  require  the  application  of  con- 
siderable heat,  or  a  spark,  to  ignite  them. 

HOW  IRON  BREAKS. 

Hundreds  of  existing  railway  bridges  which  carry  twenty 
trains  a  day  with  perfect  safety  would  break  down  quickly 
with  under  twenty  trains  an  hour,  writes  a  British  civil  en- 
gineer. This  fact  was  forced  on  my  attention  nearly  twenty 
years  ago,  by  the  fracture  of  a  number  of  iron  girders  of 
ordinary  strength  under  a  five-minute  train  service.  Simi- 
larly, when  in  New  York  last  year,  I  noticed,  in  the  case  of 
some  hundreds  of  girders  on  the  elevated  railway,  that  the 
alternate  thrust  and  pull  on  the  central  diagonals  from  trains 
passing  every  two  or  three  minutes  had  developed  a  weak- 
ness which  necessitated  the  bars  being  replaced  by  stronger 
ones,  after  a  very  short  service.  Somewhat  the  same  thing 


273 

I  ':.  tc  be  done  recently  with  a  bridge  over  th^  river  Trent, 
but,  the  train  service  being  small,  the  life  of  the  bars  was 
measured  by  years  instead  of  months.  Jf  ships  were  always 
among  great  waves  the  number  going  to  the  bottom  would 
be  largely  increased.  It  appears  natural  enough  to  every  one 
that  a  piece,  even  of  the  toughest  wire,  should  be  quickly 
broken  if  bent  back  and  forward  to  a  sharp  angle;  but,  per- 
haps, only  to  locomotive  and  marine  engineers  does  this  ap- 
pear equally  natural  that  the  same  results  would  follow  in 
time  if  the  bending  were  so  small  as  to  be  quite  imperceptible 
to  the  eye.  A  locomotive  crank  axle  bends  but  one  eighty- 
fourth  of  an  inch,  a  straight  driving-axle  a  still  sn.aller 
amount,  under  the  heaviest  bending  stresses  to  which  they 
a:  e  subject,  and  yet  their  life  is  limited.  During  the  year 
1883  one  iron  axle  broke  in  running,  and  one  in  fifteen  was 
renewed  in  consequence  of  defects.  Taking  iron  and  steel 
axles  together,  the  number  then  in  use  on  the  railways  of  the 
United  Kingdom  was  14,847,  and  of  these  911  required 
renewal  during  the  year.  Similarly,  during  the  past 
three  years,  no  less  than  228  ocean  steamers  were  disabled 
by  broken  shafts,  the  average  safe  life  of  which  is  said  to  be 
about  three  or  four  years.  Experience  has  proved  that  a 
very  moderate  stress,  alternating  from  tension  to  compres- 
sion, if  repeated  about  100,000,000  times,  will  cause  a  frac- 
ture as  surely  as  bending  to  an  angle  only  ten  times. 

VALUE  OF  EMERY  WHEELS. 

The  increased  quantity  and  quality  of  work  that  goes  on* 
of  the  modern  machine  shop  is  clue  to  the  skillful  use  of  solid 
emery  wheels.  A  grain  of  sand  from  the  common  grind- 
stone, magnified,  would  look  like  a  cobble  stone,  a  fracture 
of  which  shows  an  obtuse  angle,  wnereas  a  grain  of  corun- 
dum or  emery  would  look  lik^  a  rhomboid,  always  break- 
ing with  a  square  or  concave  fracture.  No  matter  how  much 
it  is  worn  down  in  use,  it  does  not  lo.se  its  sharpness ;  hence 
it  is  evident  that  the  grindstone  rubs  or  grinds  and  heats 
the  work  brought  in  contact  with  it,  while  the  corundum,  or 
emery  wheel,  *"ith  its  sharp,  angular  grit,  cuts  like  a  file  or 
angular  saw. 

There  are  two  general  classes  of  emery  wheels  in  the 
market — one  class  of  wheels  has  the  grains  of  emery  joined 
and  consolidated  by  a  pitchy  material,  as  rubber,  linseed  oil, 
shellac,  etc.  These  must  run  at  a  high  speed  to  burn  out  the 
cementing  material  by  friction,  loosening  the  worn-out  grains, 
and  thus  revealing  new  cutting  nnirk-s.  The>e  ar.;  non-i  -  n  its 


274 

wheels.  Truing  up  this  class  of  wheels  is  done  with  a  dla» 
moml  tool. 

The  other  class  consists  of  two  kinds,  one  made  by  mix- 
ing the  emery  with  a  mineral  cement  and  water  into  a  paste, 
whit  h  will  harden  and  bind  the  grains  together ;  the  other 
kind,  by  mixing  the  emery  with  a  mineral  flux  or  clay,  mold- 
ing into  shape,  and  burning  in  a  muffle  at  a  high  tempera- 
ture. These  are  porous  wheels,  in  which  the  grains  of  emery 
are  held  together  by  matter  having  affinity  therefor.  This 
class  of  wheels,  unlike  the  grindstone,  has  sharp  grains  of 
emery  bedded  together  among  matter  which,  in  some  cases, 
is  as  hard  and  sharp  as  the  emery  itself.  Such  wheels  cut 
very  greedily,  and  do  not  need  to  be  run  at  any  particular 
speed. 

The  dresser,  made  of  hardened  steel  picks,  is  the  proper 
tool  for  truing  up  this  class  of  wheels. 

Manufacturers  in  metal  goods  aiming  at  reducing  the  cost 
of  production,  would  do  well  to  look  into  the  adaptability  of 
the  solid  emery  wheels  or  rotary  file,  and  other  labor-saving 
machinery,  before  deciding  on  reducing  labor  wages. 

THE  SECRET  OF  CAST  STEEL. 

The  history  of  cast  steel,  remarks  a  contemporary,  pre- 
sents a  curious  instance  of  a  manufacturing  secret  stealthily 
obtained  under  the  cloak  of  an  appeal  to  philanthropy.  The 
main  distinction  between  iron  and  steel,  as  most  people  know, 
is  that  the  latter  contains  carbon.  The  one  is  converted  into 
the  other  by  being  heated  for  a  considerable  time  in  contact 
with  powdered  charcoal  in  an  iron  box.  Now,  steel  thus 
made  is  unequal.  The  middle  of  a  bar  is  more  carbonized 
than  the  ends,  and  the  surface  more  than  the  center.  It  is, 
therefore,  unreliable.  Nevertheless,  before  the  invention  of 
cast  steel,  there  was  nothing  better.  In  1760  there  lived  at 
Attercliffe,  near  Sheffield,  a  watchmaker  named  Huntsman. 
He  became  dissatisfied  with  the  watch-spring  in  use,  and  set 
himself  to  the  task  of  making  them  homogeneous.  "If," 
thought  he,  "  I  can  melt  a  piece  of  steel  and  cast  it  into  an 
ingot,  its  composition  should  be  the  same  throughout."  He 
succeeded.  His  steel  soon  became  famous.  Huntsman's 
ingots  for  fine  work  were  in  universal  demand.  He  did  not 
call  them  cast  steel.  That  was  his  secret.  About  1780  a 
large  manufactory  of  this  peculiar  steel  was  established  afc 
Attercliffe.  The  process  was  wrapped  in  secrecy  by  every 
means  within  reach.  One  midwinter  night,  as  the  tall  chim. 
nevs  of  the  Attercliffe  steel  works  belched  forth  their  sir.oke 


275 

a  traveler  knocked  at  the  gate.  It  was  bitterly  colcl,  and  the 
snow  fell  fast,  and  the  wind  howled  across  the  moat.  The 
stranger,  apparently  a  plowman  or  agricultural  laborer  seek- 
ing shelter  from  the  storm,  awakened  no  suspicion.  Scan- 
ning the  wayfarer  closely,  and  moved  by  motives  of  humanity, 
the  foreman  granted  his  request,  and  let  him  in.  Feigning 
to  be  worn  out  with  cold  and  fatigue,  the  old  fellow  sank 
upon  the  floor,  and  soon  appeared  to  sleep.  That,  however, 
was  far  from  his  intention.  He  closed  his  eyes  apparently 
only.  He  saw  workmen  cut  bars  of  steel  into  bits,  place 
them  in  crucibles,  and  thrust  the  crucibles  into  a  furnace. 
The  fire  was  urged  to  its  extreme  power  until  the  steel  was 
melted.  Clothed  in  wet  rags  to  protect  themselves  from  the 
beat,  the  workmen  drew  out  the  glowing  crucibles  and 
poured  their  contents  into  a  mold.  Mr.  Huntsman's  factory 
had  nothing  more  to  disclose.  The  secret  of  making  cast 
Steel  had  been  discovered. 

IRON  AND  STEEL  MAKING  IN  INDIA. 

Indian  Engineering,  in  a  recent  issue,  gives  a  most 
interesting  account  of  the  manufacture  of  iron  and  steel  in 
India,  which  we  reproduce  below: 

Notwithstanding  the  simplicity  of  their  processes,  the 
iron  turned  out  by  the  natives  is  of  superior  quality,  and  is 
selling  very  cheaply;  so,  for  instance,  a  mound  of  horseshoes 
sells  at  Rs.  seven,  and  of  clamp  iron  Rs.  six-eighths.  These 
low  prices  are  accounted  for  by  cheap  fuel,  the  rich  ores,  the 
miserably  cheap  labor,  and  the  absence  of  managing  expenses. 

There  are  reasons  to  believe  that  "Wootz"  (Indian 
cast  steel)  has  been  exported  to  Asia  Minor  more  than  2,000 
years  ago;  how  long,  however,  its  manufacture  has  been 
commenced,  cannot  be  traced. 

The  following  is  a  description  of  the  method  for  making 
"  Wootz"  employed  by  the  natives  at  Hyderabad. 

The  minute  grains  or  scales  of  iron  are  diffused  in  a 
sandstone-like  gneiss  or  mica  schisti  passing  into  a  horn- 
blende slate.  These  rocks  are  excavated  with  crowbars,  and 
then  crushed  between  stones;  if  hard,  this  is  done  after  prelim- 
inary roasting. 

The  ore  is  then  separated  from  the  powdered  rock  by 
washing.  This  was  at  a  village  called  Dundurti,  but  the  pro- 
cess of  manufacture  was  ths  same  as  that  at  Kona  Samun- 
drum,  twelve  miles  south  of  the  Godavari,  and  twenty-five 
from  Nirmal,  which  has  been  described  by  Dr.  Voysey.  The 
furnace  was  made  of  a  refractory  clay,  derived  from  deccm- 


276 

posed  granite,  and  the  crucibles  are  made  of  the  same,  ground 
t«  a  powdei  together  with  fragments  of  old  furnace  and 
broken  crucibles  kneaded  up  with  rice,  chaff  and  oil.  He 
states  that  no  charcoal  was  put  into  the  crucible,  but  some 
fragments  of  old  glass  slag  were.  A  perforation  was  made 
^n  the  luted  cover.  Two  kinds  of  iron,  one  from  Mirtapalli 
and  the  other  from  Kondaporc,  were  used  in  the  manufacture 
of  the  steel.  The  former  was  made  from  magnetic  sand, 
and  the  latter  from  an  ore  found  in  the  iron  clay  (?  laterite) 
twenty  miles  distant;  the  proportions  used  of  each  were 

3  to  2. 

This  mixture  being  put  into,  the  crucible  in  small  pieces, 
the  fire  was  kept  up  at  a  very  high  heat  for  twenty-four  hours 
by  means  of  four  bellows,  and  was  then  allowed  to  cool 
down.  Cakes  of  steel  of  great  hardness,  and  weighing  on  the 
average  i%  Ibs.,  were  taken  from  each  crucible.  They  were 
then  covered  with  clay  and  annealed  in  the  furnace  for  twelve  to 
sixteen  hours;  then  cooled,  and,  if  necessary,  the  annealing  was 
repeated  till  the  requisite  degree  of  malleability  had  been 
obtained.  The  Telinga  name  for  thi>  steel  was  "  Wootz," 
and  "  Kurs"  or  cake  of  it,  weighing  1 10  rupees,  was  sold  on 
the  spot  for  eight  annas.  The  daily  produce  of  a  furnace 
was  50  seers,  or  in  value  Rs.  37. 

Also  Mysore  is  a  country  where  the  manufacture  of  iron 
and  steel  by  the  natives  was  of  great  importance  owing  to  the 
excellent  quality  of  its  produce. 

_  The  iron  was  made  from  black  sand,  which  the  torrents, 
formed  in  the  rainy  season,  brought  down,  from  the  rocks. 
The  furnaces  in  the  Chin-Narayan  Durga  taluk  were  on  a 
small  scale",  the  charge  of  ore  being  42^  pounds,  from  which 
about  47  per  cent,  of  the  metal  was  obtained.  Work  was 
carried  on  for  only  four  months,  the  smelters  taking  to  culti- 
vation du-  ing  the  remainder  of  the  year.  The  stone  ore  was 
smelted  in  the  same  way  as  the  iron  sand,  but  the  latter,  it  is 
said,  was  alone  fit  for  manufacturing  into  steel.  There  were 
in  this  vicinity  five  steel  forges,  four  in  the  above  taluk,  and 
ODe  at  Devaraya,  Durga. 

The  furnace,  of  which  a  figure  is  given  by  Buchanan,  con- 
sisted of  a  horizontal  ash-pit  and  a  vertical  fire-place,  both 
sunk  below  the  level  of  the  ground.  The  ash-pit  was  about 
three-fourths  of  a  cubit  in  width  and  height,  and  was  con- 
nected with  a  refuse  pit  into  which  the  ashes  could  be  drawn. 
The  fire-place  was  a  circular  pit,  a  cubit  in  width,  which  was 
connected  with  the  a>h-pit,  being  from  (he  surface  of  the 
ground  to  the  bottom  two  cubits  in  depth.  A  screen  or  mud- 
wall  five  feet  high,  protected  the  bellows-man  from  heat  and 


277 

sparks.  The  bellows  were  of  the  ordinary  form,  a  conical 
leather  sack  with  a  ring  at  the  top,  through  which  the  opera- 
tor passed  his  arm. 

The  crucibles,  made  of  unbaked  clay,  were  conical  in  form, 
and  of  about  one  pint  capacity.  Into  each  a  wedge  of  iron 
and  three  rupees'  weight  of  the  stem  of  the  Cassia  Auricu- 
la ta  and  two  green  leaves  of  a  species  of  convolvulus  or  Jpo~ 
maia  were  put.  The  mouths  of  the  crucibles  were  then 
covered  with  round  caps  of  unbaked  clay,  and  the  junctures 
well  luted. 

They  were  then  dried  near  the  fire,  and  were  ready  for  the 
furnace.  A  row  of  them  was  first  laid  round  the  sloping 
mouth  jof  the  furnace;  within  these  another  row  was  placeci. 
and  the  center  of  the  dome,  so  formed,  was  occupied  by  * 
single  crucible,  making  nfteef.  \\\  ic!l 

The  crucible  opposite  the  bellows  was  then  withdrawn, 
and  its  place  occupied  by  an  empty  one,  which  could  be 
withdrawn  in  order  to  supply  fuel  below.  The  furnace,  being 
filled  with  charcoal,  and  the  crucibles  covered  with  the  same, 
the  bellows  were  plied  for  four  hours,  after  which  the  opera- 
tion was  completed.  When  the  crucibles  were  opened,  the 
steel  was  found  melted  into  a  button  with  n  sort  of  crystalline 
structure  on  its  surface,  which  showed  that  complete  fusion 
had  taken  place.  These  buttons  weighed  about  twenty-four 
rupees.  There  were  thirteen  men  to  each  furnace,  a  head 
man  to  make  and  fill  the  crucibles,  and  four  relays  of  three 
men  each,  one  to  attend  the  furnace,  and  two  for  the  bel- 
lows. 

Each  furnace  manufactured  forty-five  pagodas'  worth  of 
1, 800  wedges  of  iron  into  steel.  The  net  profit  was  stated 
to  be  1,253  fanams,  but  into  the  further  details  as  to  cost  it 
is  not,  perhaps,  necessary  to  enter.  The  total  production  of 
steel  in  this  vicinity  was  estimated  to  be  152  cwt.,  or  about 
,£300  per  annum. 

The  principal  sources  of  the  ores  were  the  magnetic  sand 
found  in  rivers,  and  the  richer  portion  of  the  laterite. 

THE  SWISS  PATENT  LAW. 

The  Republic  of  Switzerland  has  passed  a  law  for  the  pro- 
tection of  inventions,  thus  following  in  th<?  wake  of  other' 
nations.  The  final  disposition  of  the  question,  however,  as  to 
whether  the  law  shall  be  operative  or  not,  %vill  first  require  the 
petitions  of  30,000  voters  asking  its  submission  to  the  people. 
That  point  gained,  the  law  must  then  be  submitted  to  a  vote 
and  be  approved  by  a  riajoritv  Tf,  is  not  stated  whether  the 


278 

Swiss  Government  has  a  patent  on  this  method  of  giving  a  law 
force.  It  will  take  three  months  to  carry  out  this  rigmarole. 
Material  objects,  and  not  processes,  are  protected.  It  is  said 
that  "  this  feature  is  due  to  the  efforts  of  the  manufacturers  of 
aniline  colors  and  chemicals,  whose  interests  would  be  inju- 
riously effected  by  a  law  as  comprehensive  as  that  of  the  United 
States,  which  protects  'useful  arts'  and  '  compositions  of  mat- 
ter,' as  well  as  tools  and  machines." 

HOW    BREAKS    IN    SUBMARINE    CABLES    ARE 
DETECTED  AND  REPAIRED. 

The  following  is  an  account  of  how  submarine  cables  are 
found  and  repaired  at  an  immense  depth: 

The  break,  which  the  "  Minia "  was  sent  to  repair, 
occurred  early  last  summer.  The  officers  of  the  company 
first  located  the  distance  of  the  break  from  the  stations  on 
shore,  on  each  side  of  t:\e  ocean.  The  details  of  the  instru- 
ment by  which  this  is  done  nre  not  easily  described,  though 
easily  understood  in  principle.  The  machine  consists  of  a 
series  of  coils  of  wire,  which  offr  a  known  resistance  to  the 
electric  current.  Enough  of  the  coils  are  connected  to  make 
a  resistance  equal  to  the  resistance  offered  by  the  entire  cable 
when  it  is  in  work  ing  order,  and  thus,  when  the  machine  and  " 
the  cable  are  connected,  a  balance  is  effected.  But,  if  the 
cable  should  break,  the  balance  is  destroyed,  because  that 
portion  of  the  cable  between  the  shore  station  and  the  break, 
wherever  it  may  be,  will  offer  less  resistance  to  the  electric 
current  than  the  entire  cable  would  do.  Enough  coils  of  wire 
are  therefore  disconnected  from  the  machine  to  restore  the 
balance.  The  resistance  of  the  part  of  the  cable  that 
remains  intact  is  thus  accurately  determined  by  the  number 
of  coils  remaining  connected  with  the  machine.  Having, 
when  the  cable  was  intact,  learned  the  resistance  which  a 
mile  of  the  cable  offers,  by  dividing  the  entire  resistance  by 
the  number  of  miles  of  cable,  it  is  easy  to  find  how  many 
miles  of  cable  are  still  in  good  order,  by  dividing  the  entire 
resistance  of  the  piece  by  the  known  resistance  of  one  mile 

Having  determined  how  many  miles  from  the  shore 
station  the  break  is,  orders  are  sent  to  go  to  the  place,  pick  up 
the  ends,  and  splice  them  to  new  piece.  Having  received  such 
an  order  and  acted  on  it,  Captain  Trott  found  himself  and 
his  ship,  on  July  25th  last,  in  latitude  42°  30'  north,  and 
longitude  46°  30'  west,  or  just  to  the  eastward  of  the  Grand 
Banks  of  Newfoundland,  with  one  of  the  hardest  jobs 
before  him  that  he  had  had  in  some  time,  for  sounding 


showed  that  the  water  was  about  13,000  feet,  or  a  good  deal 
more  than  two  miles  deep.  He  knew  he  was  somewhere 
near  the  break  in  the  cable,  but  he  did  not  know  absolutely 
within  about  three  or  four  miles,  because,  while  he  had  been 
able  to  determine  his  own  position  by  repeated  observations 
of  the  sun  and  stars,  he  could  not  tell  how  accurate  the 
observations  of  the  officers  of  the  ship  laying  the  cable  ^ad 
been. 

The  first  work  done  was  to  get  a  scries  of  soundings  over 
u  patch  of  the  sea  aggregating  twenty-five  or  thirty  sd1— "«* 
miles.  The  sounding  apparatus  consisted  of  an  oblong  sncn 
of  iron,  weighing  about  thirty-two  pounds,  attached  to  a 
piano  forte  wire  in  such  a  way  that,  when  lowered  to  the  bottom, 
the  shot  would  jab  a  small  steel  tube  into  the  mud  down 
there,  and  would  then  release  itself  from  the  wire,  and  allow 
the  sailors'  to  draw  up  the  tube  with  the  mud  in  it.  The 
moment  the  weight  was  released,  the  men  on  deck  stopped 
paying  out  the  wire,  and  thus,  knowing  how  much  wire  had 
been  run  out,  they  were  able  to  tell  the  depth.  It  is  a  fact 
that  it  took  twenty-four  minutes  and  ten  seconds  for  the 
weight  of  the  ounding  apparatus  to  reach  bottom  in  2,097 
fathoms  of  water. 

The  ship  was  now  ready  to  begin  the  search  proper  for 
the  cable.  She  was  run  off  at  right  angles  to  the  line  of  the 
cable  for  r.  distance  of  five  miles,  and  a  buoy  got  down  to 
mark  the  limits  of  the  territory  to  be  grappled  ov-r  in  that 
direction.  Buoys  were  afterward  ret  elsewhere  to  mark  the 
other  limits  of  the  territory.  The  grappling  iron  was  low- 
ered over  'he  bows,  the  rope  attached  to  it  passing  o.ver  one 
of  the  three  big  grooved  wheels  that  revolve  where  the  bow- 
sprit of  an  ordinary  vessel  stands. 

The  grappling  iron  used  is  the  invention  of  Captain  Trott. 
It  looks  something  like  a  four-pronged  anchor.  It  has  a  shaft 
four  feet  long,  and  four  arms  about  a  foot  long,  that  are  set 
at  right  angles  to  each  other  at  the  bottom  of  the  shaft. 
Right  in  each  crotch  formed  by  the  arms  is  a  little  button 
that  has  a  spring  behind  it  that  may  be  regulated  in  strength. 
The  button  projects  a  third  of  an  inch  into  the  crotch.  The 
angle  of  the  arms  with  the  shaft  is  so  small  that  a  rock  could 
not  get  down  in  so  far  as  to  reach  the  button ;  but,  when  the 
cable  is  caught  by  the  hooks,  it  presses  down  against  the  but- 
ton, and  thus  closes  an  electrical  circuit  through  a  copper 
wire  running  through  the  grapnel's  rope  and  the  grapnel 
itself,  and  a  bell  is  set  ringing  upon  deck.  But  the  experi- 
enced m  n  in  charge  of  the  grappling  are  generally  able  to 
telJ  who ;  the  hook  has  hold  of  without  the  aid  of  the  bell. 


2  So 

They  judge  by  the  strain  on  the  rope,  which  is  indicated  by  a 
dynamometer  on  deck.  The  ordinary  strain  on  the  dyna- 
mometer is  from  3  to  3^  tons  when  the  grapnel  is  dragging 
freely  over  a  smooth  bottom  as  the  vessel  forges  slowly  ahead. 
Sometimes  a  rock  catches  on  the  hooks.  This  frequently 
breaks  off  an  arm,  but  sometimes  it  fetches  clear,  the  strain 
indicated  by  the  dynamometer  informing  the  old  sailor  man 
in  charge  whether  an  accident  has  happened  or  not. 

It  took  two  hours  and  twenty  minutes  to  get  the  grap- 
pling iron  from  the  bow  of  the  ship  down  to  the  bottom  of  the 
sea,  13,000  feet  below.  The  cable  used  to  drag  it  with  is  the 
patent  wire  and  hemp  invention  of  the  captain.  The  drag- 
ging began  on  July  25th,  the  clay  of  arrival,  but  they  swept 
backward  and  forward  over  the  territory  for  ten  days  without 
finding  the  broken  telegraph  cable.  A  good  part  of  .the  time 
they  wt  re  steaming  back  and  forth  d.iy  and  night,  and  the 
only  time  when  they  were  not  doing  so  was  when  the  weather 
was  too  bp'-l.  On  such  occasions  they  went  to  the  buoy  at 
the  supposed  end  of  the  broken  cable,  and  hove  to  till  the 
gale  was  ended. 

Finally,  on  August  5th,  the  bell  rang,  indicating  that  the 
grapnel  had  caught  the  cable.  The  grapnel  drag  rope  was 
thereupon  fastened  to  a  buoy  and  thrown  overboard.  Then 
the  steamer  went  off  two  miles  toward  the  end  of  the  broken 
cable  and  got  out  a  cutting  grapnel.  This  is  like  the  other 
one,  except  that  there  are  knives  in  the  crotches.  When 
these  crotches  catch  the  cable  and  strain  comes  on  them,  th_ 
cut  the  cable  off  clean. 

"  Why  did  you  cut  off  the  cable  there?  "  was  asked. 

"  Because,  if  we  had  tried  to  get  up  the  bight  of  the  cable 
where  we  first  found  it,  the  cable  might  have  broken  under 
the  strain.  That  cable  was  laid  in  1869,  and  is  getting 
pretty  well  along  in  years.  It  would  have  been  as  apt  to 
break  on  the  shore  side  as  the  other,  but,  when  we  had  only 
an  end  of  two  miles  to  deal  with,  we  were  sure  of  being  able 
to  get  up  without  damage.  We  grappled  European  end  first." 

Having  cut  off  the  cable,  the  vessel  returned  to  the  buoy 
on  the  grappling  rope,  and,  getting  the  rope  inboard  again, 
led  it  to  a  drum  six  feet  in  diameter  located  on  the  uppel 
deck  and  operated  by  a  steam  engine.  Then  they  began  to 
wind  in  the  grapnel  rope  and  hoist  the  old  cable  to  the  bows. 
They  started  the  drum  at  1:20  in  the  afternoon  of  August  5, 
8x1  at  7:51  had  the  bight  of  it  at  the  bow  of  the  ship.  Then 
the  two  miles  and  odd  of  end  that  was  hanging  down  from 
the  bow  was  fished  up  and  stretched  in  lengths  along  the 
deck  until  the  end  was  reached  This  was  connected  uirh  a. 


28l 

very  complete  cable  telegraph  office  located  amidships,  and 
a  second  later  the  operators  who  had  been  on  watch  for  days 
in  the  British  station  awaiting  this  event  saw  the  {lashes  on  a 
mirror  in  their  fftce  that  told  them  all  about  it. 

Sometimes  it  happens  that,  when  an  end  of  the  cable  is 
picked  up  in  this  way,  and  an  attempt  is  made  to  communi- 
cate with  the  shore,  it  is  found  that  there  is  another  break, 
and  that  they  have  only  the  end  of  an  odd  section  lying 
loose.  Then  they  have  to  drop  that  over,  after  testing  it  to 
see  how  long  it  is,  and  go  on  toward  the  shore  and  begin  over 
again.  In  this  case,  however,  they  found  that  they  had  hold 
of  a  sound  wire  to  Great  Britain.  Without  any  delay,  the 
end  of  a  new  cable  was  spliced  to  the  old  end  brought  from 
the  bottom.  Two  experts,  one  who  is  trained  in  splicing 
cores,  and  one  who  is  trained  in  splicing  the  outside  or 
sheathing,  are  employed  in  this  work. 

When  the  splice  was  completed  and  tested,  and  found 
perfect,  the  cable  was  started,  running  out  around  drums 
and  grooved  wheels  controlled  by  brakes,  and  over  the  stern, 
the  old  end  having  been  led  fair  through  these  sheaves  before 
the  splicing  was  done.  Then  the  ship  headed  for  shoal  water, 
and  ran  away  at  from  three  to  four  knots  an  hour  until  over 
a  part  of  the  banks  where  work  could  be  done  more  easily 
than  where  the  water  was  more  than  two  miles  deep.  Of 
course  this  involved  the  abandonment  of  a  good  many  miles 
of  old  cable,  but  the  old  cable  wasn't  of  very  much  impor- 
tance anyhow. 

Arriving  in  shoal  water,  the  end  of  the  new  piece  was 
attached  to  a  buoy  and  put  overboard.  Then  the  old  cable 
was  grappled  and  cut  as  before,  and  a  new  piece  spliced  to 
it.  Then  the  ends  of  the  two  new  pieces  were  spliced  to- 
gether and  the  job  was  complete.  It  had  taken  nearly  two 
months  to  do  it,  although  in  the  meantime  two  easier  jobs 
were  attended  to,  and  a  trip  to  Halifax  for  provisions  was 
made,  not  to  mention  the  encountering  of  the  storm  that 
damaged  the  rudder. 

The  "  Minia  "  has  a  crew  of  ninety,  all  told,  including  the 
captain,  three  deck  officers,  a  navigator,  three  expert  elec- 
tricians, four  engineers,  a  purser  and  a  surgeon.  A  black- 
smith and  a  boiler  maker,  with  their  tools,  are  carried.  There 
are  three  big,  round  tanks  to  ho'd  the  600  miles  of  cable 
cariied,  which  includes  sizes  to  fit  ail  the  old  cables  under  the 
charge  of  this  shijj.  There  is  a  cell-room  where  the  electricity 
for  telegraphing  is  generated,  and  two  dynamos  with  their 
engines,  one  to  furnish  electricity  for  a  system  of  arc  lights 
used  wh^n  at  work  at  night,  and  the  other  for  the  incandes- 


282 

cent  system  that  lights  the  ship  below  decks.  The  main 
saloon  is  large,  and  is  comfortably  and  handsomely  fitted. 
The  captain  has  a  cabin  under  the  turtle-back  aft,  as  fine  as 
any  captain  could  wish  for,  and  the  other  officers  have  rooms 
below  that  are  as  well  fitted  as  those  usually  occupied  by 
naval  officers.  The  crew  are  all  expert  men,  and  get  pay 
that  averages  a  good  deal  better  than  ihe  pay  in  the  packet 
service  between  New  York  and  Liverpool.  The  entire  crew 
is  kept  under  pay  the  year  round,  the  ship  making  her  head- 
quarters at  Halifax  when  not  engaged  in  repairing  cables. 
They  are  as  comfortable  a  lot  of  sailor  men  as  one  could  find 
anywhere. 

Till'!    LONGEST  KLECTRIC    RAILROAD    IX  THE 
COUNTRY. 

The  longest  electric  railroad  in  this  country  is  one  under 
contract  at  Topeka,  Kansas.  The  length  of  the  road  is  to  be 
fourteen  miles  and  \vill  require  fifty  cars.  The  Thomson- 
Houston  system  has  been  applied. 


The  breaking  strain  on  various  metals  is  shown  in  the 
following  table,  the  si/e  of  the  rod  tested  being. in  each  case 
one  inch  square,  and  the  number  of  pounds  the  actual  break- 
ing strain  : 

Pounds. 

Hard  steel 150.000 

Soft  steel 120,000 

Best  Swedish  iron . 84,000 

Ordinary  bar  iron 70,000 

Silver 41,000 

Copper 35>ooo 

Gold 22,000 

Tin 5,500 

Zinc '.       2,600 

Lead 860 

To  make  varnish  adhere  to  metal,  add  five-hundredthsper 
cent,  of  boracic  acid  to  the  varnish. 

Machinery  will  do  almost  anything,  and  what  machinery 
can't  do  a  woman  can  with  a  hairpin. 

To  find  the  weight  of  a  cast-iron  ball,  Ilaswellsays — Mul- 
tiply the  cube  of  the  diameter  in  inches  by  1365,  and  the 
product  is  the  weight  in  pounds. 


NUMBER    OF    REVOLUTIONS    OF    WATCH 

WHEELS. 

Very  few  who  carry  a  watch  ever  think  of  the  unceasing 
labor  it  performs  under  what  would  be  considered  shabby 
treatment  for  any  other  machinery.  There  are  many  who 
think  a  watch  ought  to  run  for  years  without  cleaning,  or  a 
drop  of  oil.  Read  this  and  judge  for  yourself:  The  main 
wheel  in  an  ordinary  American  watch  makes  4  revolutions 
a  day  of  24  hours,  or  1,460  in  a  year.  Next,  the  center 
wheel,  24  revolutions  in  a  day,  or  8,760  in  a  year.  The 
third  wheel  192  in  a  clay,  or  59,080  in  a  year.  The  fourth 
wheel,  2,440  in  a  day,  or  545,600  in  a  year.  The  fifth,  or 
'scape  wheel,  12,960  in  a  day,  or  4,  728,200  in  a  year.  The 
ticks  or  beats  are  388,800  in  a  day,  or  141,882,000  in  a  year. 

A  VALUABLE  POINT  FOR  HOLDERS. 

It  is  claimed  that  a  saving,  as  well  as  a  better  job,  can  be 
effected  by  the  substitution  of  the  following  for  the  coal  dust 
and  charcoal  used  with  green  sand :  Take  one  part  common 
tar,  and  mix  with  20  parts  of  green  sand;  use  the  same  as 
ordinary  facing.  The  castings  are  smooth  and  bright,  as  tar 
prevents  metal  from  adhering  to  the  sand,  prevents  formation 
of  blisters,  and  helps  the  production  of  large  castings  by 
absorbing  the  humidity  of  the  sand. 

METRICAL  AND  CENTIGRADE  EQUIVALENTS. 

As  much  of  the  scientific  literature  of  the  steam  engine, 
the  metrical  system  of  weights  and  measures  and  the  centi- 
grade thermometrical  scale  are  used,  we  publish  the  following 
equivalents,  which  may  be  of  use  to  our  readers  in  readily 
reducing  them  to  British  units  : 

kilogrammetre. 7>233  f°ot  pounds. 

foot  pound 188  kilogrammetre. 

French   horse  power    (chevelvapeur)  75  kilo- 

grammetres  per  second 9863  horse  power. 

British  horse  power 1.0139  chevaux. 

kilogramme  per   cheval 2,239  pounds  H.  P. 

pound  per  horse  power 447  kilo,  per  chevaJL 

caloric,  or  French  heat  unit 3.968  British  unltS 

British  thermal   unit 252  caloric. 

French  mechanical   equivalent,  423.55  (usually 

called  424)    kilogrammetres 3063.  5  ft.  pounds. 

English  mechanical  equivalent,  772  footpounds  10.76    kilogrammetre 


284 

A  NEW  ALLOY. 

An  alloy,  the  electrical  resistance  of  which  diminishes 
with  increase  of  temperature,  has  recently  been  discovered. 
It  is  composed  of  copper,  manganese  and  nickel.  Another 
alloy,  due  to  the  same  investigator,  the  resistance  of  which  is 
practically  independent  .of  the  temperature,  consists  of  70 
parts  of  copper  combined  with  30  of  ferro-manganese 

USE  OF  NATURAL  GAS  IN  CUPOLAS. 

At  Pittsburgh,  Pa.,  natural  gas  has  been  utilized  in 
cupolas  for  ordinary  castings.  The  apparatus  consists  of  a 
series  of  pipes,  covered  with  fire-clay  tiles,  and,  at  the  same 
time,  ventilating  the  pipes  with  a  current  of  air.  A  combus- 
tion chamber  is  necessarily  connected  with  the  furnace,  to 
insure  the  required  heat  and  prevent  the  chilling  of  the  fur- 
nace. 

A  NEW  CEMENT. 

A  cement  called  magnesium  oxychloride,  or  white  cement, 
has  been  discovered,  and  is  now  manufactured  in  California, 
as  we  learn  from  an  exchange.  It  is  composed  of  one-half 
(l/2)  magnesium  oxide,  which  is  obtained  from  the  magnesite 
deposits  in  the  Coast  Range,  and  one-half  (^)  magnesium 
chloride,  obtained  from  various  sea-salt  manufactories 
throughout  the  State.  It  may  be  used  for  sidewalks,  and  for 
interior  decorating,  and  in  appearance  resembles  pure  white 
marble.  It  has  a  natural  polish,  and,  above  all,  is  much 
cheaper  than  any  of  the  other  substances  now  in  use. 

HOW  TO  CAST  A  FACE. 

The  person  whose  face  is  to  be  "  taken "  is  placed  flat 
upon  his  back,  his  hair  smoothed  back  by  pomatum  to  pre- 
vent it  covering  any  part  of  the  face,  and  a  conical  piece  of 
paper  or  a  straw,  or  a  quill  put  in  each  nostril  to  breathe 
through.  The  eyes  and  mouth  are  then  closed  and  the  entire 
face  completely  and  carefully  covered  with  salad  oil.  The 
plaster,  mixed  to  the  proper  consistency,  is  then  poured  in 
large  spoonfuls  to  the  thickness  of  one-quarter  or  one-half 
inch,  in  a  few  minutes  this  can  be  taken  off  as  if  it  were  a 
film.  When  a  cast  of  the  entire  head  or  of  the  whole  human 
figure  is  required,  either  a  cast  of  the  face  is  added  to  a  mass 
of  clay,  which  is  to  be  modeled  to  the  required  figure,  or  the 
whole  figure  is  modeled  from  drawings  prepared  for  thai- 
purpose  T!  >  is  the  work  of  the  sculptor. 


When  the  clay  model  is  finished,  a  mold  is  made  from  it 
as  in  the  former  cases.  If  the  model  be  a  bust,  a  thin  ridge 
of  clay  is  laid  along  the  figure  from  the  head  to  the  base,  and 
the  front  is  first  completed  up  to  the  ridge  by  filling  up  the 
depressions  two  or  three  inches  deep.  The  ridge  of  clay  is 
now  removed,  the  edges  of  the  plaster  are  o'led,  and  the 
other  half  is  clone  in  a  similar  way.  The  two  halves  are  like- 
wise tied  together  with  cords,  and  the  plaster  is  poured  in. 
In  complicated  figures,  say  a  "  Laocoon,"  the  statue  is  oiled 
and  covered  with  gelatine,  which  is  cut  off  in  sections  by 
means  of  a  thin,  sharp  knife,  each  piece  serving  as  a  Mold 
for  its  own  part  of  the  new  statue. 

MELTING  POINTS  OF  METALS. 


Metals. 

Centigrade. 

Fahrenheit. 

Aluminum  

deg 

rees         700 
425 

'£ 

264 

320 
,200 
,091 
,38l 
I76 

»530 

,200 
,400 

334 
235 
—  40 
i,  600 
62 
2,600 
1,040 
96 

235 
412 

deg 

< 

i 

rees    1,292 
797 
365 
507-2 
608 
'        2,192 
1,995.8 
<     .    2,485.  r* 
348.8 
2,786 
*        2,192 
2,552 
617 

455 
-40 
2,912 
143.6 
4,712 
1,904 
172.8 
455 
773-6 

Antimony  

Arsenic  

Bismuth      

Cadmium  

Cobalt  

Copper  

Gold  

Indium  

Iron,  wrought   

Iron,  cast  

Iron,  steel  

Lead   

Magnesium  

Mercury  

Nickel  

Potassium  

Platinum  

Silver  

Sodium  

Tin  .    .     . 

Zinc  

According  to  experiments  recently  made  at  the  Royal 
Polytechnic  School  at  Munich,  the  strength  of  camel  hair 
belting  reaches  6,215  pounds  per  square  inch,  while  that  of 
ordinary  belting  ranges  between  2,230  pounds  and  5,260 
pounds  per  square  inch. 


286 
WEIGHT  AND  SPECIFIC   GRAVITY    OF    METAL. 


Metals. 

Wt.    pr 
cubic  ft. 

Wt.   pr 

cubic  ft. 

Specific 
grav. 

Aluminum.  ...   

Lbs. 
1  66 
419 
613 

524 
534 
537 
555 
1208 
1106 
528 

450 
485 
708 
711 
849 
1344 
H36 
654 
644 
490 
455 
437 

Lbs. 
.096 
.242 
•353 
•3 
.308 

•3i 
•32 

.697 
.638 

•304 
.26 
.28 
.408 
.j.i 
.489 

•775 
.828 

•377 
•371 
.284 
.262 
.252 

2.67 
6.72 
9.822 
8.4 
8.561 
8.607 
8.9 
19.361 
17.724 

3-459 
7.21 
7.78 
11.36 
11.41 
I3-596 
21-531 
23- 
10.474 
10.312 
7-85 
7.29 

7- 

Antimony,  cast  

Bismuth  

Brass,  cast  

Bronze  

Copper,  cast  

(  '       wire  

Gold,  24  carat  

*  (     standard  

Gun-metal  

Iron,  cast  . 

"    wrought  

Lead,  cast  

"     rolled  

Mercury  . 

Platinum  

sheet  

Silver,  pure  

'*       standard  

Steel.  

Tin,  cast  

Zinc  

HOW  TO  MEND  PATTERNS. 
For  mending  patterns  needing  temporary  repairs,or  for 
making  additions  where  but  one  or  two  molds  are  to  be 
made,  the  following  material  will  be  found  very  useful. 
Melt  together  I  pound  beeswax,  i  pound  rosin  and  one 
pound  paraffine  wax.  It  is  well  to  note  here  that  the  bees- 
wax intended  is  the  wax  made  by  the  bees,  and  not  the 
wax  made  by  the  wholesale  dealers.  The  cheap  wax  sold 
to  the  shipping  houses  contains  but  a  small  portion  of 
the  article  made  by  the  bees,  and  a  large  proportion  of 
soft  paraffine  wax.  The  result  of  using  this  compound  wax 
instead  of  the  genuine  article,  in  any  mixture,  is  to  intro- 
duce too  much  paraffine  and  only  a  little  beeswax.  When 
the  genuine  article  is  used,  this  mixture  will  be  found 
very  useful  for  making  addition  to  patterns,  temporary 
patterns,  and  for  a  variety  of  purposes  in  pattern  shop. 


287 

VALUE  OF  METALS. 
Gold  by  the  pound  avoirdupois. 

Vanadium  (cryst.  fused) $4,792.40 

Rubidium  (wire) , 3,261 .60 

Calcium  (electrolyctic) 2,446.20 

Tantalum  (pure) 2,446.20 

Cerium  (fused  globules) 2,446.20 

Eithium  (globules) 2,228. 79 

Lithium  (wire) 2,935.44 

Lubium  (fused) ,67 1 .57 

Didymium  (fused) ,620.08 

Strontium  (electrolyctic) ,576.44 

Indium  (pure) ,522.08 

Ruthenium ,304.64 

Columbium  (fused) ,250.28 

Rhodium ,032. 84 

parium  (electrolyctic) 924. 12 

ralliu'H 73&39 

Osmium 652. 32 

Palladium 498.30 

Indium. 466. 59 

Uranium 434.88 

Gold 299.72 

Titanium  (fused) 239.80 

Tellurium      "       196.20 

Chromium     "       196.20 

Platinum       "       122.31 

Manganese    " 108. 72 

Molydenum.    54-34 

Magnesium  (wire  and  tube) 45-3° 

Potassium  (globules) 22.65 

Silver 18.60 

Aluminum  (bar) 16.30 

Cobalt  (cubes) 12.68 

Nickel    3.80 

Cadmium 5.26 

Sodium 3.26 

Bismuth  (crude) 1-95 

Mercury. J  .00 

Antimony .36 

Tin.....' .25 

Copper .22 

Arsenic .15 

Zinc .10 

Lead .06 

Iron.. .1% 


288 

LENGTH  PER  COIL  AND  WEIGHT  OF  ROPE  PER 
HUNDRED  FATHOMS. 


Manila  and  Sisal  Rope. 

Tarred 
Cordage. 

Diameter  in 
inches. 

Cir.  in 
inches 

Le'gth 
in  feet. 

Lbs. 
per 
lOoFa 

Le'gth 
in  feet. 

Lbs. 
per 
loo  Fa 

#  or  6th. 

# 

1,300 

'12 

840 

18 

5-16  or  Qth. 

15-16 

1,300 

17 

840 

29 

ft  or  I2th. 

iH 

1,200 

23 

840 

40 

15  thread. 

15  thread. 

1,200 

31 

840 

47 

I  8  thread. 

1  8  thread. 

1,100 

45 

840 

58 

21  thread. 

21  thread. 

I,IOO 

5° 

840 

68 

# 

i# 

990 

'   52 

960 

64 

9-16 

# 

i# 

2 

990 

99° 

7° 
83 

960 
960 

79 
94 

*, 

2X 

990 

105 

960 

130 

% 

2^ 

99° 

125 

960 

140 

15-16 

2^? 

990 

155 

960 

170 

3  , 

99° 

175 

960 

207 

1-16 

3# 

99° 

205 

960 

238 

3-16 

3X 

990 

255 

960 

272 

X 

3^ 

990 

280 

960 

300 

S-i6 

4 

960 

310 

960 

332 

n 

4* 

960 

355 

960 

376 

yt 

4^ 

960 

410 

96o 

440 

H 

4^ 

96o 

450 

960 

505 

11-16 

5 

960 

500 

960 

573 

iH 

sX 

960 

550 

960 

610 

1% 

5K 

960 

610 

960 

654 

I  15-16 

5¥ 

960 

690 

960 

797 

2 

6 

960 

750 

960 

900 

2   3~l6 

6^ 

960 

845 

960 

1.057 

2*/S 

7 

960 

1,000 

960 

1,163 

2% 

rA 

960 

1,100 

960 

i>35^ 

2# 

8 

960 

1,270 

960 

1,613 

3 

9 

960 

i»595 

960 

2,013 

HOW  TO  MAKE  BRONZE  MALLEABLE. 

Domier  has  discovered  that  bronze  is  rendered  malleable 
by  adding  to  it  from  one-half  to  two  per  cent,  of  mercury. 


289 
WHEN  A  DAY'S  WORK  BEGINS. 

The  decision  of  the  Supreme  Court  that  a  workman  who 
has  agreed  to  do  work  at  a  specified  sum  per  hour,  is  not 
entitled  to  charge  for  the  time  spent  in  going  to  or  returning 
from  work,  is  one  that  equitably  applies  to  some  kind^of 
business,  but  not  to  others.  Where  house-building  mechan- 
ics have  several  days'  work  to  do  at  a  building,  and  their 
tools  and  materials  are  on  the  spot,  they  are  expected  t  >  re- 
port at  the  building  in  time  to  do  a  full  day's  work.  Where 
they  are  doing  odd  jobs  and  are  obliged  to  siart  from  the 
shop  in  the  morning,  they  do  so  at  the  regular  hour  for 
beginning  work,  thus  reducing  the  hours  of  actual  labor. 
But  they  must  be  paid  for  the  whole  day,  and  the  person  for 
whom  the  work  is  done  must  be  charged  for  the  time  occu- 
pied in  going  to  and  from  the  job;  otherwise,  the  "  boss" 
would  have  to  pay  his  journeymen,  for  say  tea  hours*  \\ork. 
though  accounting  for  only  s.x  hours  work'  in  his  bill  to  cus- 
tomers. In  some. of  the  small  trades  a  journeyman  will  go  to 
half  a  doze.i  houses  in  a  day,  doing  an  hour's  work  in,  each, 
and  spending  the  other  four  hours  in  passing  from  one  job  to 
another.  In  one  way  cr  another  he  is  bound  to  be  paid  for 
the  whole  time.  If  he  can  charge  only  for  the  actual  work- 
ing time,  then  his  rates  will  be  increased  so  as  to  compensate 
him  for  the  time  spent  in  service  that  is  not  to  be  paid  for. 
The  decision  shows  the  importance  of  making  agreements  of 
this  kind  specific,  both  as  to  the  rate  of  wages  and  the  hours 
and  kind  of  service. 

CAMEL'S-HAIR  BELTING. 

Camel's-hair  belting  has  been  recently  the  subject  of 
experiments  at  the  Polytechnic  school,  at  Munich,  from 
which  it  Dopears  that  the  strength  of  camel's-hair  belting 
reaches  6,315  pounds  per  square  inch,  whilst  that  of  ordinary 
belting  ranges  between  2,230  pounds  and  5,260  pounds  per 
square  inch.  A  contemporary  says  the  camel's-hair  belt  is 
said  to  work  smoothly  and  well,  and  it  is  unaffecte^  ty 
acids 

TO  PERFORATE  GLASS. 


In  drilling  glass,  stick  a  piece  of  stiff  clay  or  putty  on  tht 
part  where  you  wish  to  make  the  hole.  Make  a  hole  in  tte 
putty  the  size  you  want  the  hole,  reaching  to  the  glass,  of 
course.  Into  this  hole  pour  a  little  molten  lead,  when, 
unless  it  is  very  thick  glass,  the  piece  will  immediately  drop 


290 
HIGH    SPEED    GEARING. 

During  the  last  few  years,  and  particularly  since  the 
adoption  of  double-heliacal  teeth,  a  great  increase  has  been 
made  in  speed  at  which  gearing  is  run,  and,  in  many  cases, 
there  are  now  successfully  adopted  speeds  which  in  former 
days  would  have  been  regarded  as  utterly  impracticable. 
The  most  striking  instances  of  this  which  we  have  come 
across,  is  in  the  case  of  a  pair  of  double-heliacal  wheels  at 
the  works  of  Messrs.  R.  Johnson  &  Nephew,  the  well  known 
wire-drawers  of  Manchester.  These  wheels,  which  were  cast 
by  Messrs.  Sharpies  &  Co.,  of  Ramsbottom,  Lancashire,  are 
12  in.  wide  on  the  face,  by  6  ft.  3  in.  diameter,  and  they  have 
now  been  running  for  over  a  year  at  220  revolutions  per 
minute,  the  pitch-line  speed  being  thus  4,319  ft.  per  minuls. 
Notwithstanding  this  enormous  speed,  the  wheels  run  with 
Scarcely  any  noise,  and  their  working  has  been  most  satis- 
factory. This  is  the  highest  speed  we  have  heard  of  for 
geared  wheels,  running  iron  to  iron,  and  the  fact  that  it  ha» 
been  adopted  with  success,  is  a  most  interesting  one. 

The  large  gear  on  the  Corliss  engine  at  the  Centennial 
Exhibition  was  30  feet  in  diameter,  outside,  and  ran  at  36 
revolutions  per  minute.  It  had  a  24-in.  face,  and  the  speed 
of  the  pitch-line  is  about  3, 360  ft.  per  minute.  This  speed  is 
exceeded  by  a  similar  gear,  also  made  by  Mr.  Corliss,  which 
is  now  running  in  a  mill  in  Massachusetts.  It  is  30  ft.  in 
outside  diameter,  and  has  a  3o-in.  face.  It  makes  50  revolu- 
tions per  minute,  and  the  speed  of  the  pitch-line  is  not  far 
from  .4,670  ft.  per  minute.  This  is  probably  the  highest 
speed  at  which  any  gear  has  yet  been  run  continuously. 

The  Corliss  gears  are  all  accurately  shaped  by  a  revolving 
cutter:  but  it  is  probable  that  Messrs.  Sharpies  &  Co.'s  gears 
are  not  cut,  but  cast,  and  then  finished  up  by  hand.  If  that 
is  the  case,  their  performance  is  much  more  remarkable  than 
that  of  the  Corliss  gears. 

THE  WORLD'S  STEAM  ENGINES. 

According  to  the  Berlin  Bureau  of  Statistics,  there  is  in 
the  world  the  equivalent  of  46,000,000  horse-power  in  steam 
engines,  3,000,000  being  in  locomotives.  In  engines  other 
than  locomotives,  the  United  States  comes  first  with  7,500,- 
<X>o  horse  power;  England  next  with  7,000,000  horse  power; 
Germany  4,500,000  horse-power;  France  3,000,000  horse- 
pdwer,  and  Austria  1,500^000.  Four-fifths  of  the  si  en  in 
engines  now  in  operation  are  said  to  have  bee  i  built  within 
the  last  twenty-five  years 


291 
LIABLE  TO  SPONTANEOUS  COMBUSTION. 

Cotton-seed  oil  will  take  fire  even  when  mixed  with 
twenty-five  pe/  cent,  of  petroleum  oil ;  but  ten  per  cent,  of 
mineral  oil  mixed  with  animal  or  vegetable  oil,  will  go  far  to 
prevent  combustion. 

Olive  oij  is  combustible,  and,  mixed  with  rags,  hay  or 
sawdust,  will  produce  spontaneous  combustion. 

Coal  dust,  flour-dust,  starch  (especially  rye  flour),  are  all 
explosive  when  with  certain  proportions  of  air. 

New  starch  is  highly  explosive  in  its  comminuted  state, 
also  sawdust  in  a  very  fine  state,  when  confined  in  a  close 
»lhute,  and  water  directed  on  it.  Sawdust  should  never  be 
used  :xi  oil  shops  or  warehouses  to  collect  drippings  or  leak- 
ages from  casks. 

Dry  vegetable  or  animal  oil  inevitably  takes  fire,  when 
saturating  cotton  waste,  at  1 80°  F.  Spontaneous  combustion 
occurs  most  quickly  when  the  cotton  is  soaked  with  its  own 
weight  of  oil.  The  addition  of  forty  per  cent,  of  mineral  oil 
(density  .890)  of  great  viscosity,  and  emitting  no  inflammable 
vapors,  even  in  contact  with  an  ignited  body  at  any  point 
below  338°  F. ,  is  sufficient  to  prevent  spontaneous  combustion, 
and  the  addition  of  twenty  per  cent,  of  the  same  mineral  oil 
doubles  time  necessary  to  produce  spontaneous  combustion. 

Greasy  rags  from  butter,  and  greasy  ham  bags. 

Bituminous  coal  in  large  heaps,  refuse  heaps  of  pit  coal, 
hastened  by  wet,  and  especially  when  pyrites  are  present  in 
the  coal ;  the  larger  the  heaps  the  more  liable. 

Timber  dried  by  steam  pipes  or  hot  water,  or  hot  air 
heating  apparatus,  owing  to  fine  iron  dust  being  thrown  off, 
in  close  wood-casings,  or  boxings  round  the  pipes,  from  the 
mere  expansion  and  contraction  of  the  pipes. 

Patent  dryers  from  leakages  into  sawdust,  etc.,  oily  waste 
of  any  kind,  or  waste  cloths  of  silk  or  cotton,  saturated  with, 
oil,  varnish,  turpentine. 

HOW  COMBUSTION  IN  COAL  IS  PPODUCED. 

In  a  ton  of  anthracite  coal,  there  is  about  1,830  Ibs.  of  car-, 
bon,  70  Ibs.  of  hydrogen  and  52  Ibs.  of  oxygen;  while  a  ton 
of  good  bituminous  coal  is  composed  of  1, 600  Ibs.  of  carbon,, 
108  Ibs.  of  hydrogen  and  32  Ibs.  of  oxygen.  The  combus- 
tion of  coal  proceeds  from  its  combination  with  oxygen  gas,, 
and,  when  fuel  of  any  kind  combines  with  oxygen,  heat  is  pro*  '. 
duced.  All  bodies,  substances,  gases  and  liquids,  are  com- 
posed of  separate  particles,  often  of  molecules  of  inconceiv- 
able smp!1n;s>.  These  particles,  it  is  scientifically  conceded, 


292 

are  in  motion  among  themselves,  and  this  motion  constitutes 
feat,  for  heat  is  only  a  kind  of  motion.  This  internal  vibra- 
tion of  mfinitesirnal  particles  may  be  transmuted  into  a  per- 
ceptible mechanical  movement,  or  the  mechanical  movement 
may  be  converted  into  the  invisible  motion  called  heat.  The 
oxygen  combined  with  coal  has  a  very  considerable  range  of 
internal  motion,  and  the  combining  process  produces  carbonic 
acid  gas;  and,  the  particles  of  this  gas  having  a  much  smaller 
range  of  motion  than  the  particles  of  the  oxygen  have,  the 
difference  appears  in  the  form  of  heat. 

CAPACITY  OF  CYLINDRICAL  CISTERNS. 

The  following  table  shows  the  capacity   in    gallons  for 
each  foot  in  depth  of  cylindrical  cisterns  of  any  diameter: 
Diameter.  Gallons.  Diameter.  Gallons. 

25  ft-  3.059  7  ft-  239 

20  ft.  *>958  6^  ft.  206 

15  ft.  1,101  6  ft.  176 

14  ft.  959  5  ft.  122 

13  ft-  ^27  4#  ft.  99 

12  ft.  705  4  ft.  78 

ii  ft.  592  3  ft.  44 

10  ft.  489  2%  ft.  30 

9  ft.  396  2  ft.  19 

8  ft.  313 

HOW  TO  SELECT  A  HAND  SAW. 

A  saw-maker  has  this  advice  to  give  to  carpenters  in  the 
selection  of  a  saw: 

"See  that  it  'hangs'  right.  Grasp  it  by  the  handle  and  hold 
it  in  position  for  working  to  see  if  the  handle  fits  the  hand 
properly.  A  handle  should  be  symmetrical,  and  the  lines 
perfect.  Many  handles  are  made  of  the  green  wood;  they 
soon  shrink  and  become  loose,  the  screws  standing  above 
the  wood.  An  unseasoned  handle  is  liable  to  warp  and  throw 
the  saw  out  of  shape.  Try  the  blade  by  springing  it.  seeing 
that-  it  bends  evenly  from  point  to  butt  i  i  proportion  as  the 
•wLltli  and  gauge  of  the  saw  vary.  The  bl  ide  should  not  be 
too  heavy  in  comparison  to  the  teeth,  as  it  will  re-quire  more 
labor  to  use  it.  The  thinner  you  can  get  a  stiff  saw  she  bet- 
ter: it  makes  less  'kerf  and  takes  less  muscle  to  drive  it. 

"•See  that  the  saw  is  well  set  and  has  a  good  crowning 
breast.  Pluce  ir,  at  a  distance  from  you;  .net  a  pr«p«r  light 
on  it.  and  you  can  see  if  there  has  been  any  imperfections  in 
grinding  or  hammering." 


FBOM  ONE  TON  OF  COAL. 

From  one  ton  of  ordinary  gas  coal  may  be  produced  1,500 
pounds  of  coke  20  gallons  of  ammonia  water  and  140  pounds 
of  coal  tar.  By  destructive  distillation  the  coal  tar  will 
yield  69.5  pounds  of  pitch.  17  pounds  of  creosote.  14  pounds 
of  heavy  oils.  9,5  pounds  of  naphtha  yellow,  6.3  pounds  <>f 
naphfha'in^.  4. 75  p  Minds  of  iriphtix*!.  2  25  pounds  of  solvent 
na'.Ki'h.i.  1  5  pounds  of  i>hen<>!.  1.2  pounds  of  aurine,  1.1 
pounds  of  benzine,  1  1  pounds  «>f  analine,  0.77  of  a  pound  of 
loludine,  0.46  of  a  pound  of  anthracine  and  0.9  of  a  pound  of 
toulene.  Prom  the  latter  is  obtained  the  new  substance 
known  as  saccharine,  which  is  530  times  as  sweet  as  the  best 
cane  sugar,  one  part  of  it  giving  a  vei  y  sweet  taste  to  a  thou- 
sand parts  of  water. 

HOW  TO  SELECT  ROPE. 

A  German  paper,  in  an  article  on  the  present  methods  of 
rope  manufacture  from  hemp,  and  the  determination  of  the 
different  qualities  and  the  probable  strength  simply  from  the 
appearance,  lays  down  the  following  rules:  A  good  hemp 
rope  i .;  hard  hut  pliant,  yellowish  and  greenish  gray  in  color, 
with  a  certain  .silvery  or  pearly  Lister.  A  dark  or  blackish 
color  indicates  that  the  hemp  has  suffered  from  fermentation 
in  the  process  of  curing,  and  brown  spots  show  that  the  rope 
was  spun  while  the  fibers  were  damp,  and  is  consequently- 
weak  and  soft  in  those  places.  Again,  sometimes  a  rope  is 
made  with  inferior  hemp  on  the  inside,  covered  with  yarns 
of  good  material  —  a  fraud,  however,  which  may  be  detected 
by  dissecting  a  portion  of  the  rope,  or,  in  practical  hands,  by 
its  behavior  in  use  ;  other  inferior  ropes  are  made  with  short 
fibers,  or  with  strands  of  unequal  strength  or  unevenly  spun 
—  the  rope  in  the  first  case  appearing  wooly,  on  account  ol 
the  number  of  ends  of  fiber  projecting,  and,  in  the  latter 
case,  the  irregularity  of  manufacture  is  evident  on  inspection 
by  any  good  judge. 

THINGS  THAT  WILL  NEVER   BE  SETTLED. 

Whether  a  long  screw-driver  is  better  than  a  short  one 
of  the  same  family. 

Whether  water-wheels  run  faster  at  night  than  they  do  in 
the  day  time. 

The  best  way  to  harden  steel. 

Which  side  of  the  belt  should  run  next  to  the  pulley. 

The  proper  speed  of  line  shafts. 

The  right  way  to  lace  belts. 

Whether  compression  is  economical  or  the  reverse. 

The  principle  of  the  steam  injector. 


294 
THINGS  WORTH  KNOWING. 

Dominer  has  discovered  that  bronze  is  rendered  malleable 
by  adding  to  it  from  one-half  to  two  per  cent,  of  mercury. 

An  "  inch  of  rain  "  means  a  gallon  of  water  spread  over  a 
surface  of  nearly  two  square  feet,  or  a  fall  of  about  loo  tons 
on  an  acre  of  ground.. 

A  steam  power  plant  is  divided  into  five  fundamental 
parts  by  a  French  author  —  the  boiler,  motor,  condenser, 
distributing  mechanism,  and  mechanism  of  transmission. 

Turpentine  and  black  varnish,  put  with  any  good  stove 
polish,  is  the  blackening  used  by  hardware  dealers  for  polish- 
ing heating  stoves.  If  properly  put  on,  it  will  last  throughout 
the  season. 

A  workman  in  the  Carson  mint  has  discovered  that  drill 
points,  heated  to  a  cherry-red  and  tempered  by  being  driven  * 
into  a  bar  of  lead,  will  bore  through  the  hardest  steel  or  plate 
glass  without  perceptibly  blunting. 

To  harden  copper,  melt  together,  and  stir  till  thoroughly 
incorporated,  copper  and  from  one  to  six  per  cent,  of  mand- 
ganese  oxide.  The  other  ingredients  for  bronze  and  other 
alloys  may  then  be  added.  The  copper  becomes  homogene- 
ous, harder  and  tougher. 

SIMPLE  TESTS  FOR  WATER. 

Boiler-users  who  desire  simple  tests  for  the  water  they 
are  using  will  find  the  following  compilation  of  tests  both 
useful  and  valuable : 

Test  for  Hard  or  Soft  Water—  Dissolve  a  small  piece 
of  good  soap  in  alcohol.  Let  a  few  drops  of  the  solution 
fall  into  a  glass  of  the  water.  If  it  turns  milky,  it  is  hard 
water;  if  it  remains  clear,  it  is  soft  water. 

Test  for  Earthy  Matters  or  Alkali — Take  litmus-paper 
dipped  in  vinegar,  and,  if  on  immersion  the  paper  returns 
to  its  true  shade,  the  water  does  not  contain  earthy  matter 
or  alkali.  If  a  few  drops  of  syrup  be  added  to  a  water  con- 
taining an  earthy  matter,  it  will  turn  green. 

Test  for  Carbonic  Acid — Take  equal  parts  of  water 
and  clear  lime  water.  If  combined  or  free  carbonic  acid  is 
present,  a  precipitate  is  seen,  to  which,  if  a  few  drops  of 
muriatic  acid  be  added,  effervescence  commences. 

Test  for  Magnesia — Boil  the  water  to  twentieth  part  of 
its  weight,  and  then  drop  a  few  grains  of  neutral  carbonate 
of  ammonia  into  a  glass  of  it  and  a  few  drops  of  phosphate 
oCsoda.  If  magnesia  is  present,  it  will  fall  to  the  bottom. 


Tist  for  Iron — Boil  a  little  nut-gall  and  add  to  the 
water.  If  it  turns  gray  or  slate-black,  iron  is  present. 
Second:  Dissolve  a  little  prussiate  of  potash,  and,  if  iron  U 
present,  it  will  turn  blue. 

Test  for  Lime — Into  a  glass  of  water  put  two  drops  of 
oxalic  acid,  and  blow  upon  it.  If  it  gets  milky,  lime  is  present 

Test  for  Acid — Take  a  piece  of  litmus-paper.  If  it 
turns  red,  there  must  be  acid.  If  it  precipitates  on  adding 
lime  water,  it  is  carbonic  acid.  If  a  blue  sugar  paper  is 
turned  red,  it  is  a  mineral  acid. 

Test  for  Copper — If  present,  it  will  turn  bright 
polished  steel  a  copper  color.  Second :  A  few  drops  of 
ammonia  will  turn  it  blue,  if  copper  is  present. 

Tests  for  Lead — Take  sulphureted  gas  and  water  in 
equal  quantity  to  be  tested.  If  it  contains  lead,  it  will  turn 
a  blackish  brown.  Again  :  The  same  result  will  take  place 
\f  sulphate  of  ammonia  be  used. 

T*est  for  Sulphur — In  a  bottle  of  water  add  a  little 
q  '^silver,  cork  it  for  six  hours,  and,  if  it  looks  dark  on 
tli  pp,  and  on  shaking  looks  blackish,  it  proves  the  presence 
of  sulphur. 

JAPANESE   LACQUER  FOR   IRON  SHIPS. 

The  Japanese  Admiralty  has  finally  decided  upon  coating 
the  bottoms  of  all  their  ships  with  a  material  closely  akin  to 
the  lacquer  to  which  we  are  so  much  accustomed  as  a 
specialty  of  Japanese  furniture  work.  Although  the  prep- 
aration differs  somewhat  from  that  commonly  known  as 
Japanese  lacquer,  the  b^se  of  it  is  the  same — viz.,  gum-lac, 
as  it  is  commonly  termed.  Experiments,  which  have  been 
long  continued  by  the  Imperial  Naval  Department,  have 
resulted  in  affording  proof  that  the  new  coating  material 
remains  fully  efficient  for  three  years,  and  the  report  on  the 
subject  demonstrates  that,  although  the  first  cost  of  the 
material  is  three  times  the  amount  of  that  hitherto  employed, 
the  number  of  dockings  required  will  be  reduced  by  its  use  to 
the  proportion  of  one  to  six.  \  vessel  of  the  Russian  Pacific 
fleet  has  already  been  coated  with  the  new  preparation, 
which,  the  authorities  say,  completely  withstands  the  fouling 
influences  so  common  in  tropical  waters.  It  took  the  native 
inventor  many  years  to  overcome  the  tendency  of  the  lac  to 
harden  and  crack;  but  having  successfully  accomplished  this, 
the  finely-polished  surface  of  the  mixture  resists  in  an  almost 
perfect  degree  the  liability  of  barnacles  to  adhere  or  weeds  *o 


296 

grow,  while,  presumably,  the  same  high  polish  must  materi- 
ally reduce  the  skiu  friction  which  is  so  important  an  elejnent 
affecting  the  speed  of  iron  ships.  The  dealers  in  gum-lac 
express  the  fear  lest  the  demand  likely  to  follow  on  this  novel 
application  of  it  may  rapidly  exhaust  existing  sources  of 
supply. 

IRON  IN  THE  CONGO. 

Last  year  Mr.  Dupont,  director  of  the  Museum  of  Natural 
History  of  Brussels,  went  to  the  Congo  for  the  purpose  of 
studying  the  geology  of  the  valley  from  the  Atlantic  to  the 
confluence  of  the  Kassai  River,  over  400  miles  from  the  coast. 
After  eight  months  devoted  to  this  work,  he  has  returned  to 
Europe,  bringing  some  surprising  reports  with  regard  to  the 
mineral  resources  of  the  region.  He  says  that  throughout 
the  entire  extent  of  the  country  he  found  in  the  plateaus 
skirting  the  river,  under  the  thick  alluvium,  a  stratum  of  iron 
ore  from  a  foot  and  a  half  to  three  feet  in  thickness.  In 
numerous  places  he  saw  blocks  of  iron  ore  sometimes  many 
cubic  feet  in  dimensions,  upon  the  slopes  of  ravines,  where 
they  had  been  exposed  by  denudation.  He  asserts  that  there 
is  scarce' y  a  country  in  the  world  so  rich  in  iron  ore  as  the 
Cor^o  basin,  and  the  mineral  is  not  only  abundant,  but  can 
also  be  easily  reduced.  In  his  opinion,  if  the  other  continents 
ever  exhaust  their  resources  of  iron,  the  Congo  basin  can  sup- 
ply the  rest  of  the  world  for  a  long  period. 

GLASS  CUTTING  BY  ELECTRICITY. 

The  cutting  of  glass  tubes  of  wide  diameter  is  another  of 
the  almost  innumerable  industrial  applications  of  electricity. 
The  tube  is  surrounded  with  fine  wire,  and  the  extremities  of 
the  latter  are  put  in  communication  with  a  source  of  electricity, 
and  it  is  of  course  necessary  that  the  wire  adhere  closely  to 
the  glass.  When  a  current  is  passed  through  the  wire,  the 
latter  becomes  red  hot  and  heats  the  glass  beneath  it,  and  a 
single  drop  of  water  deposited  on  the  heated  place,  will  cause 
a  clean  breakage  of  the  g'ass  at  that  point.  Contrary  to 
what  takes  place  with  the  usual  processes  in  the  treatment  of 
this  frangible  material,  jt  is  found  that,  the  thicker  the  sides 
of  the  tubes  are,  the  better  the  experiment  succeeds. 

They  have  been  making  38-ton  guns  at  Portsmouth, 
England,  and  are  talking  of  introducing  the  47-ton  variety. 
Nearly  35,000  people  live  at  Portsmouth  on  wages  earned  in 
doing  some  kind  of  work  on  Kn^ml''  big  guns. 


297 

OTA* NESS  CAUSED  BY    THE    ELECTRIC 
LIGHT. 

A  curious  phenomenon  was  recently  related  by  M.  D'Ar- 
sonval  before  the  French  Academy  of  Medicine.  After  gazing 
for  a  few  seconds  on  an  arc  light  of  intense  brilliancy,  he 
suddenly  became  deaf,  and  remained  so  for  nearly  an  hour 
and  a  half.  Surprised,  and  somewhat  alarmed  in  the  first 
instance,  but  reassured  by  the  d.sa]»r-e.i  ranee  of  the  symp- 
toms,, he  repeated  the  experiment  with  the  same  result. 
When  only  one  eye  was  exposed  to  the  light,  no  very  marked 
effect  was  produced. 

BROWNING  GUN  BARRELS. 

Mix  16  parts  sweet  spirits  niter,  12  parts  saturated  solu- 
tion of  sulphate  of  iron,  12  parts  chloride  of  antimony.  Bot- 
tle and  cork  the  mixture  for  a  day,  then  add  500  parts  of 
water  and  thoroughly  mix.  Clean  the  barrel  to  a  uniform 
grain  free  from  grease  and  finger  stains.  Wipe  with  a  stain- 
ing mixture  on  a  wad  of  cotton.  Let  it  stand  for  twenty-four 
hours,  scratch  brush  the  iarface  and  repeat  twice.  Rub  off 
the  last  time  with  leathei  -aioistened  with  olive  oil.  Let  dry 
a  day,  and  rub  down  \\ith  a  cloth  moistened  with  oil  to 
polish. 

SPONTANEOUS  COMBUSTION 

There  is  a  remarkable  tendency  observable  in  tissues  and 
cotton,  when  moistened  with  oil,  to  become  heated  when 
oxidation  sets  in,  and  sad  results  often  follow  when  this  is  neg- 
lected. A  wad  of  cotton  used  for  rubbing  a  painting  has 
been  known  to  take  fire  when  thrown  through  the  air.  The 
waste  from  vulcanized  rubber,  when  thrown  in  a  damp  con- 
dition into  a  pile,  takes  fire  spontaneously.  Masses  of 
coal  stored  in  a  yard  have  been  known  to  take  fire  without  a 
spark  being  applied,  and  one  cannot  be  too  careful  in 
storing  any  substance  in  which  oxidation  is  liable  to  take 
place. 

A  LARGE  LUMP  OF  COAL. 

One  of  the  largest  lumps  of  coal  ever  mined  in  the  Monon- 
gahela  Valley  was  taken  from  J.  S.  N  eels'  Cincinnati  mines, 
near  Monongahela  City,  lately.  The  block  measured  7  feet 
8  inches  long,  3  feet  5  inches  high,  and  3  feet  7  inches  wide. 
A  temporary  track  was  laid  to  the  river,  and  the  big  piece  o^ 
coal  loaded  in  a  boat,  for  Cincinua.' i. 


SCREW-MAKING  AT  PROVIDENCE,  RHODE 
ISLAND. 

It  is  not  known  when  screws  were  first  made  and  brought 
into  use.  The  first  instance  known  of  machinery  being  applied 
to  the  making  of  screws,  was  in  France,  in  1569,  by  a  man 
named  Besson,  who  contrived  a  screw-cutting  gauge  to  be 
used  in  a  lathe.  The  early  method  had  been  to  make  the  heads 
by  pinching  the  blanks  while  red  hot  between  dies,  and  then 
to  form  the  threads  by  the  process  of  filing.  In  1741  Besson's 
device  was  improved  by  Hindley,  a  watchmaker,  of  York, 
England;  and  for  a  long  time  the  watch-makers  of  that 
country  used  this  device  in  making  the  small  screws  used  in 
their  work.  The  first  English  patent  appears  to  have  been 
issued  to  Job  and  William  Wyatt,  in  1760,  for  three  machines 
— one  for  making  blanks,  another  for  nicking  the  heads,  and 
a  third  for  cutting  the  threads.  Between  that  date  and  1840 
about  ten  patents  were  issued,  only  one  of  which  is  worthy  of 
notice,  namely  that  of  Miles  Berry,  d?*ed  January  28,  1837, 
which  was  for  a  gimlet-pointed  screw.  The  first  American 
patent  was  issued  December  14,  1798,  to  David  Wilkinson,  a 
celebrated  mechanic  of  Rhode  Island.  '  The  next  American 
patent  was  dated  March  23,  1813,  and  was  issued  to  Jacob 
Perkins,  of  Newburyport,  Mass.  In  that  year,  also,  a  patent 
was  granted  to  Jacob  Sloat,  of  Ramapo,  N.  Y.  At  the  exten- 
sive  nail  and  iron  works  of  the  Piersons,  established  in  Ram- 
apo in  1798,  Thomas  W.  Harvey  in  1831  applied  the  tog- 
gle-joint to  the  headings  of  screws,  rivets  and  spikes.  In  1834 
Mr.  Harvey  entered  into  partnership  with  Frederick  Goodell, 
a  cotton  manufacturer  of  Ramapo,  and  established  a  small 
screw  manufactory  at  Poughkeepsie,  and  early  in  the  next 
year  Mr.  Harvey  invented  machines  for  heading,  nicking  and 
shaving  screws.  These  and  a  thread-cutting  machine,  pur- 
chased from  its  inventors,  Jacob  Sloat  and  Thomas  Spring- 
steen, were  successfully  operated,  producing  a  gimlet-pointea 
screw. 

It  is  interesting  to  note  that,  while  the  manufacture  of 
wood  screws  probably  originated  in  Westphalia,  Germany, 
and  was  subsequently  carried  on  in  eastern  France  and  Eng- 
land before  its  introduction  into  this  country,  American  in- 
ventors have  supplied  the  machinery  that  is  now  universally 
employed.  The  popular  feeling  that  the  gimlet -pointed  screw 
was  a  modern  invention  is  erroneous.  The  company  has  in 
its  possession  sample  cards  of  French  screws,  pointed,  though 


299 

not  as  perfectly  made  as  at  present,  which  were  brought  from 
France  early  in  the  present  century,  and  from  an  old  piano 
now  at  Northampton,  made  about  the  year  1750,  screws  have 
been  taken  showing  the  same  feature.  Patents  have  been 
issued  on  gimlet-pointed  screws,  but  they  covered  only  a 
peculiar  form  of  point. 

The  Eagle  Mill  of  the  American  Screw  Company  is 
devoted  to  the  manufacture  of  wood  screws.  In  the  yard 
connected  with  this  mill  are  landed  the  rods,  in  coils,  from 
which  the  screws  are  to  be  manufactured.  The  larger  por- 
tion of  these  rods  is  .issrswDed  from  Sweden,  Germany  and 
England.  The  £r?>t;  room  into  which  the  reader  is  to  be  con- 
ducted is  the  "pickling  room."  Here  the  rod  is  "pickled" 
for  the  purpose  of  removing  the  flinty  scale  on  the  outside; 
and  the  action  of  the  mixture  in  that  process  tends  to  facil- 
itate the  drawing  of  the  wire.  After  being  annealed  in  fur- 
naces the  wire  is  subjected  to  the  pointing  process,  the  pur- 
pose of  which  is  to  reduce  the  end  of  the  rod  to  enter  the 
draw-plate.  The  wire  is  taken  into  the  drawing  room,  where 
it  is  drawn  in  different  sizes  needed  for  the  great  variety  of 
screws.  The  machinery  for  the  different  processes  is  the 
result  of  the  skill  of  many  inventors,  who  have  produced  a 
system  of  machines  mostly  automatic  and  beautiful  in  opera- 
tion. By  the  automatic  wire  block  used,  if  anything  happens 
to  the  wire  while  going  through  the  process,  the  whole  appa- 
ratus stops.  If  it  did  not  stop,  the  wire  would  break.  By  a 
machine,  whose  action  is  accurate  and  fascinating,  the  rod 
is  cut  into  the  sizes  of  the  screws  desired  and  the  head 
put  on  almost  at  the  same  instant.  The  metal,  in  going 
through  this  process,  necessarily  becomes  very  oily. 
These  "blanks,"  for  such  they  are  called  at  this  stage 
of  their  manufacture,  are  put  into  what  are  called  "rat- 
tlers," revolving  boxes,  hexagonal  in  shape,  tilled  with  saw- 
dust, where  they  are  cleansed  of  the  oil  that  covers  them,  the 
oil  eeing  absorbsed  by  the  sawdust.  The  blanks  are  ready  to 
feave  their  heads  "shaved,"  which  consists  in  cutting  the 
heads  perfectly  round.  The  blanks  are  put  into  a  hopper,  and 
by  an  automatic  feeder  they  are  let  down  into  a  trough,  from 
which  they  are  picked  by  a  metal  finger  and  put  into  a  spin- 
dle. The  heads  are  then  "shaved,"  and  by  a  revolving  spin- 
dle the  blank  is  taken  to  the  small  saw  which  cuts  the  slot  in 
the  head.  Tbe  blank  is  then  revolved  back  again  and  shaved 
again,  to  get  rid  of  the  "burr,"  or  the  rough  edge  left  by  the 
tool,  in  cutting  the  slot.  The  blanks  are  then  fired  out  of 
Vhe  machine  absolutely  perfect.  The  machine  is  an  automatic 


300 

but  very  complicated  one  ;  every  part  of  it,  however,  does  its 
work  effectively.  The  blanks,  after  being  shaved  and  slotted, 
are  placed  in  another  machine  and  threaded,  when  the  screw 
is  complete. 

HOW  THERMOMETERS  ARE  MADE. 

The  first  point,  in  the  construction  of  the  mercurial  ther- 
mometer, is  to  see  that  the  tube  is  of  uniform  caliber  through- 
out its  whole  interior.  To  ascertain  this,  a  short  column  of 
mercury  is  put  into  the  tube  and  moved  up  and  tlowr,  to  see 
if  i'.s  length  remai'  s  the  same  through  ail  parts  of  tl.e  tube. 
If  a  tube  whose  caliber  is  not  uniform  is  used,  slight  differ- 
ences  are  made  in  its  graduation  to  allow  for  this.  A  scale 
of  e  jual  parts  is  etched  upon  the  tube;  and  from  observations 
of  the  inequalities  of  the  column  of  mercury  moved  in  it,  a 
table  gj.ving  the  temperatures  corresponding  to  these  divisions 
is  formed.  A  bulb  is  now  blown  on  the  tube,  and  vhileihe 
open  end  of  the  latter  is  dipped  into  mercury,  heat  is  applied 
to  the  bulb  to  expand  the  air  in  it.  This  heat  is  then  with- 
drawn, and  theair  within  contracting,  a  portion  of  the  merci  ry 
rises  in  the  tube,  and  partly  fills  the  bulb.  To  the  open  end  of 
the  bulb  a  funnel  containing  mercury  is  fitted,  and  the  bulb 
is  placed  over  a  flame  until  it  boils,  thus  expelling  all  air  and 
moisture  from  the  instrument.  On  cooling,  the  tube 
instantly  fills  with  mercury.  The  bulb  is  now  placed  in 
some  hot  fluid,  causing  the  mercury  within  it  to  expand  and 
flow  over  the  top  of  the  tube,  and,  when  this  overflow  has 
ceased,  the  open  end  of  the  tube  is  heated  with  a  blow-pipe 
flame.  To  graduate  the  instrument,  the  bulb  is  placed  in 
melting  ice;  and,  when  the  top  of  the  mercury  column  has 
fallen  as  low  rs  it  will,  note  is  taken  of  its  position  as  com- 
pared with  the  scale  on  the  tube.  This  is  the  freezing  point. 
Jt  is  marked  as  zero  on  the  thermometers  of  Celsius  and 
Reaumur,  and  as  32°  on  the  Fahrenheit  class. 

To  determine  the  boiling  point,  the  instrument  is  placed 
in  a  metallic  vessel  with  double  walls,  between  which  circulates 
the  steam  from  boiling  water.  Between  the  freezing  and 
boiling  point  of  water,  100  equal  degrees  are  marked  in  the 
centigrade  graduation  of  Celsius,  180°  on  the  Fahrenheit 
plan,  and  80°  on  the  Reaumur.  In  many  thermometers,  all 
three  of  these  graduations  are  indicated  on  the  frame  to  which 
the  tube  is  attached.  Some  weeks  after  a  thermometer  has 
been  made  and  regulated,  it  may  be  noticed  that,  when  the 
bulb  is  immersed  in  pounded  ice,  the  mercury  does  not  quite 
descend  to  the  freezing  point  This  is  owing  to  a  gradual 
expansion  of  the  mercury,  which  usually  goes  on  for  nearly 


3oi 

two  years,  when  it  is  found  that  the  zero  point  has  risen 
nearly  a  whole  degree.  It  is  then  necessary  to  slide  dowa 
the  scale  to  which  the  tube  is  fastened,  so  that  it  will  accurately 
read  the  movements  of  the  mercury.  After  this  change,  the 
accuracy  of  the  thermometer  is  assured,  as  there  is  no  iurther 
txpansion  of  the  mercury  column. 

POINTS  FOR  APPRENTICES. 

In  starting  to  learn  a  trade  as  an  apprentice,  first  imagine 
yourself  brighter,  and  more  apt  to  learn,  than  the  older 
apprentices  in  the  shop.  Criticise  their  work  on  the  last  range* 
they  blacked.  Show  the  red  spots  under  the  doors  or  under 
the  top  plates,  and  if  you  are  not  dropped  through  the  trap 
door  into  the  cellar  the  first  opportunity  they  get,  it  will  be 
some  good  fortune  that  favors  you.  When  working  with  a 
jour.,  tell  him  how  Tom  Jones  does  that,  and  his  ways  are 
not  right,  or  tell  him  how  to  do  it.  Of  course  the  jour,  ha? 
worked  fifteen  years  at  the  business,  but  that  doesn't  make 
any  difference,  you  go  ahead.  If  he  does  not  call  you  c us* 
words  and  tell  you  to  mind  your  business,  he  must  have 
a  mother-in-law  who  comes  over  to  see  him  seven  times  a  day* 
and  stays  all  clay  Sunday. 

When  you  have  worked  about  a  year  at  the  business  and 
you  think  you  are  competent  to  take  charge  of  the  shop,  and 
you  are  given  a  job  of  cleaning  a  furnace,  which,  of  course, 
will  smut  a  boiled  shirt,  you  go  home,  and  kick  to  the  old 
folks;  say  you  are  not  going  to  work  for  Smith  any  more,  at 
he  gives  you  all  the  dirty  work  to  do,  and  get  the  old  folks  lo- 
go around  and  see  Smith  about  their  precious  boy.  It  will 
make  you,  in  the  eyes  of  Smith,  as  large  as  Jumb  )  to  a  rat. 

When  you  worry  your  term  of  apprenticeship  t!i rough 
and  you  receive  the  title  of  jour.,  of  course  you  demand  jour.'s 
wages,  say  as  much  as  old  man  Stewpot.  lie  has  worked 
eighteen  years  in  the  shop,  but  that  doesn't  matter.  Why, 
you  made  six  dozen  joints  of  stove  pipe  in  two  hours  and  it 
took  him  three.'  Well,  if  you  don't  make  satisfactory  arrange-- 
ments,  I  heard  Billy  Doepan  say  that  Enos  Ket- 1,3,  at  Inkville, 
wanted  a  man,  and  you,  of  course,  strike;  it  pays  bi^  wages  to 
o.  first-class  man.  You  go  and  see  Kettle  and  he  as' s  you 
what  you  can  do.  Of  course  you  worked  on  the  cornice  for  the 
Grand  Opera  House,  and  on  the  button  factory,  r.nd  several 
other  jobs  too  numerous  to  mention.  You  receive  n  position 
to  help  Kettle  out  on  the  Green  building  cornice.  Thi.>  being 
Thursday  night,  and  hs  has  to  go  to  Piumtoun  to  CIT.  -n  up  a 
job,  he  would  like  to  have  you  come  on  m  the  morning.  He 


302 

gives  you  a  simple  piece  of  cutting  to  keep  you  going  until  his 
return-on  Saturday  night,  when  he  makes  a  practice  of  paying 
off  his  help.  You  come  under  this  head,  and  find  that  he  offers 
you  the  enormous  sum  of  seventy-five  rents  per  day.  and  orders 
the  stove  porter  to  go  and  cover  the  pig  trough  with  your  two 
days'  work  to  keep  the  pigs  from  making  post  holes  ir  iheir 
trough,  which  his  wife  wanted  him  to  do  for  the  past  nine 
months.  You  declare  he  is  a  crank;  you  are  going  West,  or 
to  some  seaport  town. 

You  strike  out  and  get  a  position  in  a  roofing  shop  paint- 
ing tin.  You  write  home  to  your  brother  chip  telling  what 
a  position  you  have,  what  big  wrages,  etc. ,  but  not  giving 
original  facts.  In  a  few  years  you  return  home  broken 
down,  with  no  trade.  You  can't  demand  a  mechanic's 
wages,  and  you  look  back  and  see  your  folly.  How  many 
are  there  in  this  boat  ?  Boys,  take  my  advice:  Don't  get 
to  knowing  too  much.  Jf  you  get  into  that  way,  it  is  little 
use  for  a  mechanic  to  have  anything  to  do  with  you. 

THREE  THERMOMETER  SCALES. 

Much  annoyance  is  caused  by  the  great  difference  in 
thermometer  scales  in  use  in  the  different  civilized  countries. 
The  scale  of  Reaumur  prevails  in  Germany.  As  is  well  known, 
he  divides  the  space  between  the  freezing  and  boiling  points 
into  80°.  France  uses  that  of  Celsius,  who  graduated  his 
scale  on  the  decimal  system.  The  most  peculiar  scale  of  all, 
however,  is  that  of  Fahrenheit,  a  renowned  German  physi- 
cist, who  in  171401*  1715  composed  his  scale,  having  ascer- 
tained that  water  can  be  cooled  under  the  freezing  point 
without  congealing.  He  therefore  did  not  take  the  congeal- 
ing point  of  water,  which  is  uncertain,  but  composed  a  mix- 
ture of  equal  parts  of  snow  and  salammonia,  about — 14°  R. 
This  scale  is  preferable  to  both  those  of  Reaumur  and  Celsius, 
or,  as  it  is  called,  Centigrade,  because  :  i.  The  regular  tem- 
peratures of  the  moderate  zone  move  within  its  two  zeros, 
and  can  therefore  be  written  without  +  or  — .  2.  The  scale 
is  divided  so  finely  that  it  is  not  necessary  to  use  fractions, 
when  careful  observations  are  to  be  made.  These  advan- 
tages, although  drawn  into  question  by  some,  have  been  con- 
sidered so  weighty,  that  both  Great  Britain  and  America  have 
retained  the  scales,  while  the  nations  of  the  Continent  use  the 
other  two.  The  conversion  of  any  one  of  these  scales  into 
another  is  very  simple.  I.  To  change  a  temperature  given 
by  Fahrenheit's  scale  into  the  same  given  by  the  Centigrade 
scale,  subtract  32°  from  Fahrenheit's  degrees  and  multiply 


303 

the  remainder  by  f .  The  product  will  be  the  temperature 
in  Centigrade  degrees.  To  change  from  Fahrenheit's  to 
Reaumur's  scale,  subtract  32°  from  Fahrenheit's  degrees,  and 
multiply  the  remainder  by  •$.  The  product  will  be  the  tem- 
perature in  Reaumur's  degrees.  3.  To  change  a  temperature 
given  by  the  Centigrade  scale  into  the  same  given  by  Fahren- 
heit, multiply  the  Centigrade  degrees  by  §,  and  add  32°  to 
the  product.  The  sum  will  be  the  temperature  by  Fahren- 
heit's scale.  4.  To  change  from  Reaumur's  to  Fahrenheit's 
scale,  multiply  the  degrees  on  Reaumur's  scale  by  -J,  and  add 
32°  to  the  product.  The  sum  will  be  the  temperature  by 
Fahrenheit's  scale.  Following  is  a  table  giving  the  equiva- 
lents in  Centigrade,  Reaumur  and  Fahrenheit,  up  to  boiling 
point,  which  will  be  a  convenience  to  all  readers  who  do  not 
like  the  labor  of  converting  one  scale  to  another  : 


C. 


R, 


F. 


—30 

—  24.0 

—  22.0 

—29 

—  23.2 

—  20.2 

—28 

—22.4 

-I8.4 

—27 

—21.6 

—16.6 

—26 

—20.8 

—14.8 

—25 

—  20.  0 

—13.0 

—24 

—19.2 

—  II.  2 

—23 

—18.4 

—9.4 

—  22 

-17.6 

-7.6 

—21 

—  16.8 

-5.8 

—2O 

—  16.0 

—4.0 

—  19 

—15.2 

—2.2 

—  1  8 

—14.4 

—0.4 

—17 

-13-6 

1,4 

—  16 

—  12.8 

3-2 

—15 

—  I2.O 

5-o 

—14 

—II.  2 

6.8 

—13 

—  IO.4 

8.6 

—12 
—  II 

-9.6 

-8.8 

10.4 

12.2 

—  IO 

—8.0 

I4.O 

3 

-7.2 
-6.4 

15.8 

17.6 

—7 

-5.6 

19.4 

—6 

—4.8 

21.2 

—5 

—  4.0 

23.0 

—4 

—3-2 

24.8 

—3 

—2.4 

26.6 

~-2 

—1.6 

28.4 

C. 


8 
9 

10 

ii 

12 
13 
H 
15 

16 

17 

18 

19 

20 
21 

22 

23 

24 

25 
26 

27 


R. 


F. 


Up,  8 

30.2 

o.o 

32.0 

0.8 

33.8 

1.6 

35.6 

2.4 

37.4 

3-2 

39-2 

4.0 

41.0 

4.8 

42.8 

5-6 

44.6 

6.4 

46.4 

7.2 

48.2 

8.0 

50.0 

8.8 

51.8 

9.6 

53-6 

10.4 

55-4 

II.  2 

57.2 

12.0 

59-o 

12.8 

60.8 

43-6 

62.6 

144 

64.4 

15.2 

66.2 

16.0 

68.0 

16.8 

69.8 

17.6 

71.6 

18.4 

73-4 

19.2 

75-2 

20.  o 

77.0 

20.8 
21.6 

78.8 
80.6 

304 


c. 

R. 

F. 

C. 

R. 

F. 

28 

22.4 

82.4 

65 

52.0 

149.0 

29 

23.2 

81.2 

66 

52-8 

150.8 

3° 

24.0 

86.0 

67 

53-6 

152.6 

3» 

24.8 

87.8 

68 

54-4 

154-4 

32 

25-6 

89.  6 

69 

55-2 

156.2 

33 

26.4 

91.4 

76 

56.0 

i5S.c 

34 

27.2 

93-2 

S6.8 

159-8 

35 

28.0 

95  o 

72 

57-6 

161-6 

36 

28.8 

96.8 

73 

163-4 

37 

29.6 

98.6 

74 

59-2 

165-2 

38 

30-4 

too.  4 

75 

60.0 

167-0 

39 

31.2 

I  O2.  2 

76 

(10.8 

168-8 

40 

32.0 

104.0 

77 

61  6 

170-6 

4* 

32-8 

105.8 

78 

624 

1724 

42 

33-6 

107.6 

79 

63.2 

174.2 

43 

H-4 

109.4 

80 

64.0 

176.0 

-14 

35-2 

III.  2 

81 

64.8 

177.8 

45 

I  13.0 

82 

65.6 

179.6 

46 

}6.8 

114-8 

83 

66.4 

181.4 

47 

37-6 

116.6 

84 

67.2 

1832 

48 

38.4 

118.4 

85 

68.0 

185.0 

49 

39-2 

I  2O.  2 

86 

68.8 

1  86.  8 

5° 

40.0 

122.0 

87 

19.6 

188.6 

51 

40.8 

123.8 

88 

70.4 

190.4 

52 

41.6 

125.6 

89 

71.2 

192.2 

53 

42-4 

127.4 

90 

72.0 

194.0 

54 

43-2 

129.2 

91 

72.8. 

195.8 

55 

44.0 

I3I.O 

92 

73-6 

197.6 

56 

44-8 

132.8 

93 

74-4 

199.4 

57 

45-6 

134.6 

94 

75-2 

201.2 

58 

46-4 

95 

76.0 

2O3.O 

59 

47-2 

J&2 

90 

76.8 

204.8 

60 

48.0 

140.0 

97 

7^.0 

206.6 

61 

48.8 

141.8 

98 

78.4 

2O8.4 

62 

49-6 

143.6 

98 

79.2 

210.2 

63 

50-4 

145-4 

luO 

80.0 

212.0 

64 

51  2 

147.2 

WHY  STEEL  IS  HARD  TO  WELD. 

A  metallurgist  gives,  as  a  reason  why  steel  will  not  weld  as 
readily  as  wrought  iron,  that  it  is  not  partially  composed  of 
cinder,  as  seems  to  be  the  case  with  wrought  iron,  which 
assists  in  forming  a  fusible  alloy  with  the  scale  of  oxidation  on 
the  surface  of  the  iron  in  the  furnace. 


305 

DIFFERENT    COLORS     OF    IRON,    CAUSED     BY 
HEAT. 


Deg. 
Cen. 

Deg. 
Fah. 

261 

502 

f  Violet,  purple  and  dull  blue. 
1  Between  261°  C.  to  370°  C.  it 

370 

680 

^  passes  to  bright  blue  sea 

[_  green,  and  then  disappears. 

f  Commences  (o  be  covered 

|  with  a  light  coating  of  ox- 

500 

932 

<j  ide  ;  becomes  a  deal  more 

j  impressible  to  the  hammer, 

(  and  can  be  twisteel  with  ease. 

525 

977 

Becomes  a  nascent  red. 

700 

I2Q2 

Somber  red. 

800 

1472 

Nascent  cherry. 

900 

1657 

C  herry. 

1000 

1832 

Bright  cherry. 

IIOO 

2OI2 

i  hill  orange. 

I2OO 

2192 

Bright  orange. 

1300 

2.372 

White. 

1400 

2552 

Brilliant  white-welding  heat. 

1500 
1600 

2732 
291^ 

-  Dazzling  white. 

TO  DRAW  FERRULES. 

A  useful  tool  for  drawing  thimbles  or  ferrules  out  of  loco- 
motive boiler  tubes 
is  here  shown.  It  is 
an  English  inven- 
tion, and  it  is  not 
stated  that  it  is  pat- 
ented. The  tube  A 
is  split  in  quarters  on 
the  enel  so  that  it 
can  be  easily  slipped 
in.  The  rest  of  the 
device  explains  itself, 

as  does  the  sev  ond  figure  also,  which  IP  another  device  for  the 

same  purpose. 


306 
BELTING  SHAFTING  AT  EIGHT  ANGLES. 

vn  Fig.  1  of  the  illustration,  A  is  the  driver.  The  belt 
leaves  the  pulley  at  C,  goes  to  the  driven  pulley,  and  then 
down  to  the  driver  at  h.  In  Fig.  2  this  movement  is  re- 


Fig.  i.  Fig.  2. 

versed.  Fig.  3  is  a  side  view  of  the  driven  pulley  Z?,  and  Fig. 
4  shows  the  driving  pulley  A,  with  the  driven  pulley  B  in- 
side, so  as  to  run  in  the  one  direction,  while  the  dotted  linesf 


Show  B  outside,  so  as  to  run  the  opposite  way.     Figs,  i  and  t 
show  that  centers  of  the  faces  of  both  pulleys  must  be  in  line 


307 

with  each  other,  and  if  this  point  is  attended  to  the  pulleys 
will  run  well  together,  although  they  may  be  of  different 
diameters. 

AN  EASY  WAY  TO  LEVEL  SHAFTING. 

The  device  here  illustrated  for  leveling  shafting  I  have 
found  to  be  very  handy.  The  hangers  A.  are  made  of  wood 
and  are  cut  at  an  angle  of  45  o  at  the  top  end,  so  that  they  will 
fit  different  sized  shafts,  and  a  slot  is  cut  at  (a)  to  receive  the 
straight  edge  C.  The  hangers  are  placed  on  the  shaft  to  be 


tried,  at  any  convenient  place  as  near  the  bearings  as  possi- 
ble, and  the  straight  edge  placed  in  the  slots,  in  which  it 
should  fit  tight.  Then  by  placing  the  spirit  level  D  on  the 
parallel  part  of  the  straight  edge,  it  \vill  be  seen  whether  the 
shaft  is  level  or  not.  It  is  best  ff  the  hangers  be  made  of 
hard  wood. 

A   SELF-WINDING  CLOCK   MOVEMENT. 

A  self-winding  clock  is  now  on  the  market  and  we  present 
herewith  an  engraving  of  one.  It  is  made  by  the  American 
Manufacturing  and  Supply  Co.,  Limited,  10  and  12  De$r 
street,  New  York.  Objection  may  be  made  to  the  employ- 
ment of  a  battery  as  an  auxiliary,  and  therefore  that  the  clock 


Is  not  self-winding,  but  the  office  of  the  battery  is  secendaij; 
the  operation  of  the  clock  opening  the  circuit  while  the  bat- 
tery is  used  only  to  interrupt  it.  Appended  is  a  description 
Of  the  movement: 


The  wheels  and  arbors  below  the  center  are  removed  from 
the  clock.  In  their  place  a  small  electric  motor  is  substituted. 
This  motor  connects  with  a  spring  barrel  on  the  center  arbor, 
which  incloses  a  spring  six  feet  long,  three-sixteenths  of  an 
inch  in  widtft  and  six-one-thousandths  of  an  inch  in 
thickness.  This  spring,  at  its  inner  end,  is  attached 


309 

to  the  arbor,  and  at  the  ou.ef  end  to  the  periphery  of  the 
^pring  barrel.  The  spring  is  coiled  around  the  arbor  many 
times,  but  not  so  close  as  to  'produce  friction  between  the 
Coils;  and  being  attached  to  the  center  arbor  it  follows  that 
the  inner  end  will  unwind  one  turn  every  hour.  By  a  sim- 
ple attachment  the  electric  circuit  is  made  to  pass  into  the 
motor  already  referred  to,  which  quickly  carries  the  spring 
barrel  around  once  (being  free  on  the  arbor),  and  the  outer 
end  of  the  spring  attached  to  its  periphery  with  it.  Upon 
the  completion  of  one  revolution  of  the  spring  barrel,  as  de- 
scribed, the  electric  circuit  is  broken  and  the  motor  stops. 
By  this  arrangement  it  will  be  observed  that  the  inner  end  of 
the  spring  always  has  a  motion  from  left  to  right,  or  in  the 
direction  the  hands  are  moving,  and  the  outer  end  of  the 
spring  a  motion  in  the  same  direction  when  the  clock  is 
being  wound. 

Now,  since  the  winding  is  done  in  the  same  direction  as 
the  unwinding  of  the  inner  end,  and  the  spring  is  SO  wound 
originally  as  to  avoid  friction  between  the  coils,  it  follows 
that  the  tension  upon  the  train  is  absolutely  uniform  at  all 
times  whether  the  outer  end  of  the  spring  is  at  a  point  of  tem- 
porary rest  or  is  being  carried  around  the  arbor  at  the  time 
of  winding,  as  above  "described.  By  actual  experiment  it  is 
found  that  to  obtain  a  given  force  at  the  escape  wheel  it  is 
only  necessary  to  apply  a  power  in  this  manner  at  the  center 
arbor  equal  to  less  than  one  forty-sixth  part  of  that  used  in 
the  ordinary  clock.  The  train  work  is  not  only  shortened 
one-half,  but  the  fricfion  on  the  remainder  is  reduced  in  the 
proportion  stated. 

The  invention  lies  in  bringing  a  motor  and  clock-work 
together  in  a  time  piece,  and  is  not  limited  to  any  particular 
device.  Experiments  prove  that  a  motor  as  constructed  for 
this  purpose  can  be  run  for  one  year  at  an  expense  of  less 
than  twenty-five  cents;  hence  a  clock  may  be  sealed  up  and 
left  to  itself  for  a  period  of  at  least  one  year  with  a  certainty 
of  closer  time  during  that  period  than  can  be  secured  by  any 
other  known  method  of  giving  time.  In  short,  a  common 
clock  constructed  on  this  principle  has  been  found  to  keep  as 
accurate  time  as  one  of  the  higher  grades  with  gravity 
escapements,  etc.,  run  by  the  old  methods.  The  electric 
motor  is  normally  out  of  circuit,  but  at  stated  intervals,  by 
the  operation  of  the  clock  itself,  the  circuit  is  completed  and 
the  motor  is  thus  set  in  motion.  To  be  more  exact  we  will 
give  a  general  description  of  the  mechanism  employed  in  the 
clock.  Upon  the  center  arbor  there  is  placed  a  loose  "  arm  M 
between  the  hour  wheel  and  the  wheel  carrying  the  spring 


'oox.  At  one  side  of  one  of  the  "  train  plates  "  is  secured 
an  insulated  spring  connector,  Jhe  free  end  of  which  extends 
to,  and  is  within  reach  of,  the  "  arm,"  when  the  same  has  been 
brought  to  a  perpendicular  position,  which  is  done  by  means 
of  a  pin  projecting  from  the  hour  wheel. 

When  the  hour  wheel  has  thus  brought  the  "  arm"  to  an 
jpright  position  and  in  contact  with  the  insulated  spring 
connector,  the  circuit  is  completed  through  the  motor,  which 
at  once  commences  to  rotate  the  spring  box  one  revolution 
from  left  to  right,  or  in  the  direction  that  the  hp.nds  move. 
Tbe  spring  box  wheel  also  carries  a  projecting  pin,  but  set  at 
aiCos  «-'».'. i<a<?e  fro^i  tb.e  rods  than  the  other  pin.  Now,  as 
the  motor  continues  cc*  ,.—-.Jj?  *'•*?  wing  box  wheel,  while 
the  spring  connector  is  resting  upon  the  "arm,"  it  follows 
that  as  soon  as  there  has  been  one  revolution  of  the  spring 
box  wheel  the  projecting  pin  upon  this  wheel  will  press  the 
"arm"  forward  and  out  from  under  the  spring  connector, 
thereby  breaking  the  circuit  and  stopping  the  motor.  This 
arrangement  prevents  the  possibility  of  the  clock]  running 
b-yond  the  regular  limit  for  winding,  and  prevents  the  motor 
when  once  set  in  operation  from  performing  more  than  the 
work  required. 

TESTS  OF  STEEL  PIPE. 

The  Riverside  Iron  Works,  of  Wheeling,  W.  Va.,  has 
carried  out  a  series  of  interesting  experiments  to  ascertain 
the  relative  corrosive  action  of  water  acidulated  with  nitric 
acid  upon  iron  and  steel  plates  cut  from  pipe.  The  water 
was  acidulated  with  one  part  of  strong  nitric  acid  in  ninety 
parts,  the  plates  being  of  the  same  dimensions,  free  from 
scale  and  grease  and  polished  bright.  In  each  case  the 
pieces  cut  from  iron  and  steel  pipe  were  hung  side  by  side  in 
the  same  acidulated  water,  the  loss  of  weight  being  deter- 
mined at  the  end  of  twenty-four  and  of  forty-eight  hours. 
One  test  was  made  by  exposing  both  surfaces  and  edges  to 
the  action  of  dilute  acid,  the  result  being  that  the  loss  in 
grains  after  twenty-four  hours  was  3. 6  in  the  case  of  iron 
from  standard  iron  pipe,  and  1. 15,  or  less  than  half,  with  steel 
pipe.  In  forty-eight  hours  the  figures  stood  6. 53  and  2.21 
grains,  respectively.  In  a  second  test  the  edges  of  the  pieces 
were  protected  from  the  action  of  the  acid  and  the  two  oppo- 
site sides  only  exposed.  In  this  test  the  loss  of  iron  after 
twenty-four  hours  was  1.89  grains^  against  0.49  grains  with 
the  steel,  and  after  forty-eight  hours  4.28  and  1.24,  respect- 
ively. The  dimensions  of  the  test-pieces  were  i]^.  ;nches 


3U 

square  by  3-16-inch  thick.  A  series  >. "  comparative  tests 
have  also  been  made  to  ascertain  the  rela\  ^  strength  of  the 
weld  of  Riverside  steel  and  standard  iron  x  *£*>.  Two  test- 
pieces  were  cut  from  Riverside  pipe,  mechanv^i  lap-weld, 
with  the  weld  at  the  middle,  and  in  a  similar  *r*v  from 
mechanical  lap  welded  iron  pipe,  in  each  case  with  \  weld 
in  the  middle.  Not  one  of  the  tests  broke  at  the  we'K  *he 
steel  showing  a  tensile  strength  of  52,400  and  66,330  pou* 
with  an  elongation  of  18.75  and  17.25  per  cent  in  8  inches 
while  the  iron  pipe  samples  showed  62,480  and  35,240  pounds 
per  square  inch,  and  an  elongation  of  2.25  and  0.50  per  cent 
Two  samples  from  a  sheet  of  Riverside  steel  lap- welded  by 
hand,  with  the  weld  in  the  middle,  showed  a  tensile  strength 
of  51,860  pounds,  and  an  elongation  of  7  per  cent,  in  8 
inches,  the  fracture  occurring  at  the  weld.  A  second  sample 
had  an  ultimate  strength  of  56,090  pounds,  elongation  13 
per  cent,  and  did  not  break  at  the  weld.  Iron  plates  cut  with 
the  grain  and  hand-welded  have  a  tensile  strength  of  44,630 
and  43,500  pounds,  respectively,  with  an  elongation  of  5  and 
4.25  per  cent.,  both  breaking  at  the  weld. 

TOOL  FOR  COUNTER-BORING. 

The  above  is  a  sketch  of  a  tool  that  will  be  found  very  con- 
venient on  many  occasions,  when 
counter-boring  work  in  the  [drill 
press;  usually  such  work  is  done  with 
a  cutter  of  the  same  shape  as  it  is 
desired  to  have  the  finished  work, 
when  if  there  is  any  scale,  as  in  cast 
iron,  it  is  very  difficult  to  get  the  cut- 
ter started.  The  tool  in  the  sketch 
entirely  obviates  that  difficulty,  as 
only  the  points  come  in  contact  with 
the  scale  at  first  and  are  easily  forced 
through  it.  Referring  to  the  sketch, 
A  is  the  end  of  a  cutter-bar,  B,  the 
cutter,  and  C,  the  wedge  for  keeping 
the  cutter  in  place.  It  will  be 
noticed  that  the  teeth  D,  on  one  side 
of  the  bar  will,  as  it  is"  revolved, 
cover  the  space  left  by  the  part  of 
the  cutter  on  the  other  side  of  the 
bar,  and  thus  rapidly  remove  the 
scale  and  metal,  when  the  work 
may  be  finished  by  the  ordinary  flat 
cutter. 


HO^V  TO  MAKE  A  SMALL  STORAGE  LATTERY. 

A  storage  battery,  or  accumulator,  to  light  an  incandes- 
cent lamp  of  4  candle-power,  would  not  jgo  in  an  ordinary 
sized  pocket,  because  one  would  require  at  least  four  cells, 
and  if  the  plates  were  made  too  small,  the  charge  put  into 
them  would  last  scarcely  a  few  seconds.  The  following  di- 
rections will  enable  any  person  to  construct  a  storage  bat- 
tery, which,  when  charged,  will  light  a  4-volt  lamp. 

The  first  thing  to  do  is  to  procure  of  some  dealer  in  elec- 
trical apparatus  and  material  a  hard  rubber  cell,  about  $}4 
inches  by  5  inches  by  i  inch,  having  two  compartments  of 
equal  dimensions.  Such  a  cell  can  be  purchased  for  about 
fifty  cento. 

Next,  cut  four  plates  from  one-sixteenth  inch  sheet  lead, 
4%  inches  by  i^  inch,  having  an  ear  to  each;  punch  as 
many  holes  in  each  plate  as  you  can  to  within  ^  inch  from 
the  ear  or  top  end.  Then  fill  up  the  holes,  and  also  smear 
the  plates  with  a  thick  paste  of  red  lead  (minimum)  and  di- 
luted sulphuric  acid.  Cut  out  a  piece  from  thin  —  >g  of  an 
inch  —  hard  wood,  3^  inches  long  and  i  inch  wide  ;  pierce 
it  with  four  s  its  large  enough  to  allow  the  ears  of  the  plates 
to  come  through  (two  to  each  cell),  and,  also,  where  con- 
venient, two  holes  s!:ou!d  be  made  and  fitted  with  glass  tubes 
for  the  purpose  of  fiiiing  the  cells. 

As  s  ion  as  the  rod  lead  paste  has  become  hard,  plac  thee 
four  p!a'es  i  \  their  positions,  and  solder  the  ear  of  one  plate 
to  the  ear  piece  of  the  next  cell.  This  will  leave  cue  free  end 
from  each  cell;  to  these  a  wire  or  terminal  should  be  sol- 
dered. Now  cement  on  the  top  and  cover  all  over,  except 
the  g^ss  tubes,  wit'1  a  composition  of  one  part  melted  pitch 
and  two  par's  of  gutta-percfia, 

Having  filled  the  eel's  three-quarters  full  with  a  10  per 
cent,  solution  of  sulphuric  acid,  connect  the  wires  on  a 
primary  battery  or  s  nail  dynamo.  Charge,  discharge  and 
reverse  every  three  hours,  and  let  the  last  charge  remain  in 
all  night.  Do  this  till  you  find  your  storage  battery  will 
ring  a  bell,  with  fifteen  minutes'  charging,  for  about  ten. 
Then  only  charge  one  way,  and  mark  the  ends  in  some  way. 
so  as  to  know  where  to  connect  one  next  time  lor  charging. 

This  battery,  when  completed,  will  light  a  3  or  4  volt 
iamp  well  during  intervals  for  about  two  hours.  A  similar 
cell,  having  four  compartments  instead  of  two,  would  suffice 
to  operate  an  8  or  9  volt  lamp,  or  one  of  about  6  candle- 
Dower. 

Such    a    battery    as    has   just    been    described    may  be 


veniently  be  formed  by  a  ten-cell  Daniel  telegraph  battery  in 
about  a  fortnight's  time. 

A  storage  battery  of  this  size  should  never  be  charged 
until  within  an  hour  or  so  of  its  being  wanted  for  use,  as  it 
will  run  down  a  little  by  short  circuiting,  owing  to  the  damp- 
ness of  the  inside. 

Finally,  it  should  be  stated,  that,  before  putting  the  plates 
in  the  cells  for  good,  a  piece  of  india  rubber  ought  to  be 
placed  between  the  plates,  as  well  as  a  piece  on  the  two  out- 
sides,  and  held  by  a  piece  of  asbestos  fiber.  This  prevents  the 
plates  from  touching  each  other,  and  also  keeps  them  from 
shaking  from  side  to  side. 

LUBRICATING  WITHOUT  OIL. 

Several  interesting  facts  in  regard  to  cylinder  lubrication 
were  brought  out  at  the  recent  meeting  of  the  American 
Society  of  Mechanical  Engineers,  a'.  Philadelphia.  Among 
other  things  Mr.  Denton  stated  as  b  s  opinion  that  the  fric- 
tion of  an  engine  was  independent  of  the  lead,  and,  among 
other  things,  presented  the  subjoined  interesting  table: 


Indicated  II.  P. 

Friction, 

H.  P.  Kind  of  engine. 

84   

7 

10 

5 
5-i 

44 
40 

'9 

25 

{ 
\ 

I 
\ 

\ 

Westinghouse, 
I2xu     inches, 
300    revolut's. 
Buckeye,     7x14 
inches,  280  re- 
volutions. 
Compound  con- 
densing throt- 
tled. 
Compound  con- 
d  e  n  s  i  n  g-  ex- 
pans  ion. 

Unloaded  

23     .......                 ... 

Unloaded  

"347.  . 

185  

181       

I  27.  . 

This  table,  it  will  be  observed,  shows  that  the  friction  is 
actually  less  in  all  cases  but  one  when  the  load  is  greatest. 
Mr.  Denton  thought  that  the  friction  of  a  piston  in  a  cyl- 
inder was  slight,  and  that  lubrication  did  not  bring  about  any 
noticeable  result  so  far  as  this  particular  part  was  concerned. 
In  support  of  these  statements  he  cited  first  the  case  of  aa 
engine  in  which  the  steam  of  the  same  pressure  was  admitted 
to  both  cylinder  ends  at  the  same  time  The  difference  in 
area  between  the  two  faces  of  the  piston  nwingr  to  the  pres- 
ence of  the  piston-rod,  and  the  conseciu^ntly  greater  effective 


3H 

pressure  on  the  back,  as  compared  with  the  frc  ^ace,  caused 
the  piston  to  move  slowly  to  the  front  end  of  tv  Cylinder. 
The  friction,  therefore,  could  not  have  been  appreci. .  \.  As 
regards  lubrication  Mr.  Denton  gave  an  accoun!  O  his 
experience  with  engines  which  had  been  cleaned  out  v>th 
ether,  and  in  which  no  oil  whatever  had  been  used  for  monthfc 
The  records  obtained  under  such  conditions,  when  compared 
with  data  from  the  same  engines  using  oil  in  the  cylinders, 
showed  no  difference  worthy  of  special  note.  The  fact  that 
engines  showed  less  friction  under  the  heavier  loads  than 
under  the  lighter  ones  Mr.  Denton  explained  by  the  assump- 
tion that  the  various  journals,  through  the  reversal  of  motion 
of  the  reciprocating  parts  of  the  engines,  developed  a  suc- 
tion-pump action,  drawing  in  the  lubricating  oil,  and  that 
this  action  was  more  vigorous  when  the  engines  were  fully 
loaded. 

CALKING. 

Calking  is  something  that  is  not  always  done  as  it  should 
be.  In  fact,  in  some  sections  of  the  country  it  is  done  as  it 
shouldn't  be,  about  as  emphatically  as  it  is  possible  to  do  any- 
thing. The  thing  most  particularly  referred  to  in  this  con- 
nection, and  the  practice  of  which  should  bankrupt  any 
boilermaker,  is  known  as  "  split  calking."  To  do  calk- 
ing in  the  best  manner,  and  as  it  should  be  done,  the  edges 
of  the  plates  should  be  planed.  They  are  planed  in  all  first- 
class  shops,  and  trouble  caused  by  bad  calking  is  something 
very  rare  with  such  work.  But  of  course  this  refers  to  new 
work.  Repair  jobs,  and  boiler  work  turned  out  of  the  shops 
in  remote  sections  of  the  country  where  planers  are  unknown, 
afford  the  demon  of  split  calking  a  chance  to  get  in  his  most 
effective  work.  He  rarely  neglects  a  chance  that  is  offered 
him.  Some  one  may  inquire,  what  is  split  calking?  To 
which  we  would  reply,  split  calking  consists  in  driving  a  thin 
caulking  tool,  scarcely  one-sixteenth  of  an  inch  thick,  against 
the-  edge  of  a  sheet  so  that  a  thin  section  of  the  plate  is 
driven  in  between  the  two  plates,  with  the  idea  of  making  a 
joint  tight.  The  result  generally  is  that  the  plates  are  sepa- 
rated from  the  edge  of  the  lap  back  to  the  line  of  rivets,  some- 
times as  much  as  one-thirty-second  of  an  inch,  the  only  bear- 
ing surface  outside  of  the  rivets  being  the  portion  split  off 
from  the  plate  and  driven  in  by  the  calking  tool.  This 
bearing  surface  may  be  an  eighth  of  an  inch  wide,  but  it  is 
apt  to  be  much  less,  and  no  patent  medicine  yet  discovered 
will  keep  the  seam  tight  for  any  length  of  time.  When  a 
boiler  thus  calked  gets  to  leaking  so  badly  that  it  can't  be 


run,  the  boiler-maker  is  sent  for,  and  he  usually  proceeds  to 
do  more  split  calking,  and  in  a  short  time  the  boiler  leaks 
worse  than  ever.  In  one  instance  one  of  our  inspectors 
examined  a  boiler  and  found  one  of  the  girth  seams  leaking 
badly.  It  had  repeatedly  been  calked  in  the  above  manner; 
so  many  times,  in  fact,  had  the  process  been  repeated,  that 
there  was  not  enough  of  the  Jap  to  perform  another  opera- 
tion on.  He,  therefore,  gave  instructions  for  putting  on  a 
patch,  with  a  special  caution  to  the  owner,  to  whom  he  ex- 
plained the  cause  of  the  trouble,  to  allow  no  split  calking  to 
be  done  on  it.  On  his  next  visit  he  examined  the  patch,  and 
he  declares  that  the  boiler-maker  had  put  in  on  it  the  worst 
job  of  split  calking  he  ever  saw  in  his  life. 

USEFUL  NUMBERS. 

3.l4i5926=ratio  of  diameter  to  circumference  of  circle. 
.y854=ratio  of  area  of  circle  to  square  of  its  diameter. 
33,000  minute  foot  pounds=i  HP. 
396,000  minute  inch  pounds=i  HP. 

396,000  cubic  inches  piston  displacement  per  minute  of 
engine  wheel  would  develop  I  HP.  with  I  Ib.  mean  elective 
pressure  on  the  piston. 

23,760,000  cubic  inches  piston  displacement  p^r  hour  of 
engine  developing  i  HP.  with  i  Ib.  mean  effective  pressure  on 
the  piston. 

859,375  pounds  of  water  per  hour  at  i  tt>.  pressure  pei 
square  inch  to  give  i  HP. 

55  Ibs.  mean  effective  pressure  at  600  feet  piston  speed 
gives  i  HP.  for  each  square  inch  of  piston  area. 
0.301030=^111^  logarithm  2. 
0.477121         "  ^    u          3 

0.602060  4. 

0.698970         "  5. 

0.778151         fc  6. 

0.845098         «•  "          7. 

0.903090        "  **         8. 

0.954243        "  9- 

I.OOOOOO  "  IO. 

2.3025851  times  natural  logarithm  gives  hyperbolic  log- 
arithm. 

.5000000= sine  of  30°  with  radius  i. 

.7071068        "       45°         "  i. 

.8660254         "       60°         «  i. 

9,000  to  13,000  feet  per  minute  velocity  of  circular  sa\\ 
him. 

27,000  tbs.  per  square   inch    tensile   strength  of  cast  iron. 


50,000  tr>s.  per  square  inch  tensile   strength  bf  •wrought 
iron. 

130,000  lt>s.  tensile  strength  of  steel. 
30,000  Ibs.  tensile -strength  of  sheet  copper. 
60,000  Ibs.  tensile  strength  of  copper  wire. 

100,000  Ibs.  per  square    inch==crusning   strength  of  cast 
iron. 

35,000  Tbs.  per  square  inch=crushing  strength  of  wrought 
iron. 

225,000  Ibs.  crushing  strength  of  steel. 

300  to   1,200  tons  per   square   foot  crushing  strength   of 
granite. 

6.500  Ibs.  per  square  inch  ci  u.shing  strength  of  oak. 

(Above  crushing  strengths  are  for  pieces  not  over  3  dia- 
meters in  length. ) 

600  to  1,000  feet  per  minute  of  single  leather  belt  I   inck 
wide  said  to  give  i  HP.  on  cast  iron  pulleys. 

2.645  IDS>  Per  lineal  foot  of  I  inch  round  wrought  iron. 

3.368  Ibs.  per  lineal  foot  of  I  inch  square  wrought  iron. 

40  Ibs.  per  square  foot  of  i  inch  plate  wrought  iron. 

2.45  Ibs.  per  lineal  foot  of  I  inch  round  cast  iron. 

12  times  weight  of  pine  pattern  — iron  casting. 

13  times  weight  of  pine  pattern  =  brass  casting. 
19  times  weight  of  pine  pattern  —lead  casting. 
12.2  times  weight  of  pine  pattern  —tin  casting. 
11.4  times  weight  of  pine  pattern  =zinc  casting. 

.06363  times  square  of  inches  diameter,  times  thickness  in 
inches  =  weight  of  grindstone  in  pounds. 

.8862  times  cliam.  of  circle —side  of  a  square  equaling. 
.7071  times  diam.  of  circle  =side  of  inscribed  square. 
1.1283  times  square  root  of  area  of  circle  =diam.  of  circle. 
57°  2958  in.  arc  having  length  =  radius 
•oi745^X  radius=length  of  arc  i  deg. 
9.8696044=3. 14i5926*  =  fi*. 

1.7724538=  \r  (3. 1415926)= vn. 

o.497i5=nat.  log.  3.1415926. 

i 
. 31831  =reciprocal  of  3. 1415926=— 

it 

.002/78=1-7-360=1-360. 
114.59=360^-3.1415926. 
3i83Xcircumf.  =diam.  of  circle. 
2786°  F.  =melting  point  of  iron. 
2016°  F.=melting  point  of  gold. 
1873°  F.=melting  point  of  silver. 
2160°  F.=melting  point  of  copper. 


74°°  F.=melting  point  of  zinc. 
620°  F.— melting  point  of  lead. 
475°  F.=melting  point  of  tin. 


537  Ibs.  per  cu.  ft.= 
450  Ibs.  per  cu.  ft.  = 
485  Ibs.  per  cu.  ft.  = 
708  Ibs.  per  cu.  ft.= 
490  Ibs.  per  cu.  ft.= 


'eight  of  copper, 
veight  of  cast  iron, 
veight  of  wrought  iron. 
v eight  (T  cast  lead. 
v eight  of  steel. 


27.684  cubic  inches  of    wa  er  p-jr  pound  at  32°  F 
27.759011.  in.  water  p-?r  li>.  at  70° 
036  Ibs.  par  cu.  in.  water  at  60°  F. 
62.355  Ibs   per  cu.  ft.  water  at  62  °  F. 
59.64  Ib.s  per  cu.  ft.  water  at  212  °  F. 
.54  Ibs.  anthracite  per  cu.  ft. 
40  to  43  cu.  ft.  anthracite  per  ton 
49  cu.  ft.  bituminous  coal  per  ton. 
39.3685  inches  =  I  meter. 
3.2807  feet  =  i  meter. 
1.0936  yards  =  I  meter. 
61.02  cubic  inches  =  i  meter. 
2.113  pints  =  i  liter. 
1.057  (marts  -—  I  liter. 

BUYING  OIL  AND  COAL. 

There  arc  many  establishments  which,  when  buying  oil, 
coal,  and  such  supplies,  consider  merely  the  question  of  first 
cost  irrespective  of  their  economic  value.  The  best  is  not 
necessarily  the  cheapest,  nor  is  it  necessarily  the  dearest. 
The  true  economic  value  is  due  to  the  service  it  will  per- 
foivn,  divided  by  the  price. 

We  will  take  the  case  of  coal.  Some  coal  will  evaporate 
ten  pounds  of  water  per  pound  of  coal  under  certain  condi- 
tions, and  others  only  seven.  In  the  one  case  there  will  be 
2240X10—22,403  pounds  of  water  evaporated,  and  in  the 
other  only  2240X7=15,680  pounds,  under  the  same  condi- 
tions. If  the  first  lot  sold  at  $5.25  per  ton,  and  the  second 
at  only  $5  the  first  would  be  the  cheapest,  for  in  the  one  case 
(including  freight  and  labor  in  stoking  and  cost  of  remov- 
ing ashes)  we  would  get  22,400-7-5.25=4,266.66  pounds  of 
steam  per  d  jllar's  worth  of  co:il,  and  in  the  other  only 
I  "5,680-7-5—  3, 136  pounds  of  steam  per  dollar's  worth  of  coal. 
Not  allowing  for  freight  and  the  cost  of  removing  ashes,  and 
Hot  considering  the  capacity  of  the  boiler  with  good  coal  as 
compared  with  its  capacity  with  poor,  the  first  coal  would  be 
a  schcap  at  $6.80  per  ton  as  the  second  at  $5  ;  or,  to  put 


it  the  Other  way,  the  poorer  coal  ought  10  be  sold  at  $3.85 
per  ton  to  make  it  as  cheap  as  the  better  material  at  $5.25. 
When  the  other  expenses  are  taken  into  consideration,  the 
economy  of  buying  the  better  coal  becomes  greater. 

In  the  matter  of  oils:  these  vary  in  their  lubricating 
powers,  in  their  coolness  of  running,  and  in  their  durability. 
We  will  consider  two  oils,  one  at  25  cents  per  gallon  and  the 
other  at  30,  having  the  same  lubricating  power  and  running 
equally  cool  under  fee  feed,  but  one  requiring  100  gallons  to 
keep  the  friction  down  to  a  minimum  and  the  other  taking 
onty  75  gallons  to  effect  the  same  object.  The  relative 
economy  of  these  two  oils  is  not  as  30  to  25,  or  as  120  to  100, 
but  as  30X75=2,250  to  25X100=2,500,  or  as  100  to  90; 
that  is,  the  cost  of  the  high-priced  oil  to  effect  a  given  desired 
condition  is  only  .90  the  cost  of  the  poor  oil  to  do  the  same 
thing ;  then  the  economy  is  as  100  to  90.  At  this  rate  the 
better  grade  of  oil  would  be  as  cheap  at 
ioX30_ 
7~~ =:33/i  cents  per  gallon, 

as  the  cheaper  at  25  cents ;  or  the  lower  grade  would  havp 
to  be  sold  at 

9x25 

— 22 ^  cents  per  gallon, 

to  bring  its  economy  down  to  that  of  the  better  grade  ;  and 
this  without  counting  freight,  which,  in  many  cases,  should 
be  added  to  the  invoice  price,  or  time  in  oiling,  which  is  time 
lost. 

NOTES  ON  PATTERN-MAKING. 

Never  work  with  a  dull  tool. 

Take  time  to  sharpen  and  put  your  tools  in  good  order;  it 
saves  time  in  the  end. 

Above  all,  never  use  a  dull  or  badly  "  set  "  saw.  It  will 
ruin  your  work,  sour  your  temper,  and  make  you  disgusted 
with  the  whole  world. 

If  you  are  varnishing  or  polishing  a  piece  of  work,  have 
the  room  or  shop  warm,  exclude  draught  and  dust,  and  don't 
be  in  too  big  a  hurry. 

If  you  are  polishing  in  the  lathe,  see  to  it  that  all  dust 
and  dirt  are  removed  from  the  lathe-bed  before  you  com- 
mence work. 

It  is  better,  when  possible,  to  polish  all  turned  work  in 
the  lathe.  It  always  has  a  better  appearance  for  it. 

In  making  patterns  for  castings,  if  you  have  no  experience 


319 

you  had  better  consult  some  person  who  has  had  experience. 
Patterns  are  difficult  things  for  amateurs  to  make  if  they  do 
not  understand  the  principles  of  molding  and  founding. 

White  pine  or  mahogany  makes  the  best  work  for  pat- 
terns. Lead,  brass,  copper  and  sometimes  plaster  of  Paris 
are  used  for  making  patterns;  especially  is  this  so  for  small 
fine  castings. 

Shellac  varnish  is  the  best  material  for  coating  pat- 
terns. 

Beeswax  may  be  used  for  stopping  up  holes  or  to  cover 
defects  in  patterns  if  it  is  coated  with  shellac  varnish  after- 
ward. The  beeswax  will  "  take "  the  varnish  readily,  and 
will  not  cling  to  the  ''sand,"  like  ordinary  putty. 

Shellac  varnish  may  be  mixed  with  a  little  lampblack  to 
give  it  body  and  make  a  black  pattern. 

Sometimes  pattern-makers  use  stove  polish  or  "black 
lead,"  as  it  is  called,  to  finish  their  patterns.  It  is  applied 
nearly  dry,  then  polished  with  a  brush. 

Wood  used  for  patterns  must  be  of  the  very  best  finish, 
straight  grained,  free  from  knots  or  shakes,  and  well  sea- 
soned. 

A  clean  pattern  gives  n  clean  casting,  and  much  labor 
may  be  saved  by  making  the  pattern  the  right  size,  and 
smooth  and  clean. 

After  patterns  have  been  used  they  should  be  kept  in  a 
dry  pb.ce,  as  damp  will  distort  and  otherwise  injure  them. 

Always  make  a  drawing  of  patterns  before  making.  Much 
time  and  labor  will  be  saved. 

Where  patterns  part  in  the  center  they  should  be  made 
to  separate  easily. 

Put  on  your  best  workmanship  when  pattern  making. 

AN  INTERESTING  EXPERIMENT. 

You  think  you  stand  pretty  straight,  don't  you?  Well, 
just  back  up  against  the  wall  of  a  room  and  bear  against  it 
all  over  ;  you  will  find  there  more  buckles,  short  bends  and 
offsets  between  your  head  and  your  heels  than  you  had  any 
idea  of. 

While  you  have  your  heels  against,  the  baseboard,  keep 
them  there,  and  reach  over  forward  and  touch  your  fingers  to 
the  floor,  if  you  want  a  specimen  of  upset  gravity. 

A  steel  wire  nail  mill  has  just  begun  work  at  Hamilton, 
Ont.  The  output  at  present  is  a  ton  a  day. 


320 

THINGS    TO     REMEMBER    ABOUT     SHAFTING. 

Don't  buy  light  hangers,  and  think  that  they  will  do  well 
enough,  when  your  own  judgment  tells  you  that  they  will 
spring. 

Remember  that  shafting  is  turned  one-sixteenth  inch 
smaller  than  the  nominal  size. 

Cold-rolled  and  hot-rolled  shafting  can  be  obtained  Tie 
full  size. 

The  sizes  of  shafting  vary  by  quarter  inches  up  to  uiree- 
and-a-half  inches. 

The  ordinary  run.  of  shafting  is  not  manufactured  longer 
than  from  1 8  to  26  feet. 

For  line  shafts,  never  use  any  that  is  smaller  than  one- 
and-eleven-sixteentli  inches  in  diameter,  as  the  smallest 
diameters  are  not  strong  enough  to  withstand  the  strain  of 
the  belts  without  springing. 

The  economical  speed  of  shafting  for  machine  shops  has 
been  found  to  be  from  125  to  150  revolutions  per  minute, 
and  for  woodworking  shops  from  200  to  300  revolutions. 

A  jack-shaft  is  a  shaft  that  is  us^d  to  receive  the  entire 
power  direct  from  the  engine  or  other  motor,  which  it  delivers 
to  the  various  main  shafts. 

Keep  the  shafting  well  lined  up  at  all  times,  as  this  will 
ward  off  a  breakdown,  and  avoid  a  waste  of  power. 

Know  that  the  pulleys  are  well  balanced  before  they  are 
put  in  position,  as  a  pulley  much  out  of  balance  is  quite  a 
sure  method  to  throw  shafting  out  of  line. 

Look  to  the  pulleys,  and  see  that  they  have  been  bored  to 
the  size  of  the  shaft,  for  unless  this  is  done  the  pulley  may  be 
out  of  center  on  the  shaft  and  prevent  smooth  running. 

If  possible,  apply  the  power  to  a  line  of  shqftingat  or  near 
the  center  of  its  length,  as  this  will  enable  you  to  use  the 
lightest  possible  weight  of  shafting. 

Hangers  with  adjustable  boxes  will  be  found  to  be  the 
most  convenient  for  keeping  the  shafting  in  line. 

Keep  your  drip-cups  cleaned,  and  Jo  not  allow  them  to 
overflow  or  get  loose. 

Have  a  supply  of  tallow  in  the  boxes  ;  in  case  of  acciden- 
tal heating  it  will  melt  and  prevent  cutting  ;  this  rule,  while 
good  for  general  use,  applies  particularly  to  special  cases  where 
there  is  a  supposed  liability  to  heating. 

Never  lay  tools  or  other  things  on  belts  that  are  standing 
Still,  for  they  may  I  e  forgotten  and  cause  a  breakdown  when 
the  machinery  is  started. 

Don't  attempt  to  run  a  shaft  in  a  box  that  is  too  larre  .>r 


321 

too  small,  as  you  will  waste  time  and  fail  to  secure  good  re- 
sults. 

A  loose  collar  held  by  a  set  screw  will  cause  the  collar 
to  stand  askew,  and  it  will  cut  and  wear  the  box  against 
whick  it  runs. 

In  erecting  a  line  of  shafting,  the  largest  sections  should 
be  placed  at  the  point  where  the  power  is  applied.  The 
diameter  can  then  be  gradually  decreased  toward  the  extrem- 
ities remote  from  this  point. 

Don't  put  loose  bolts  in  plate  couplings,  as  this  will  give 
no  end  of  trouble  in  cutting,  shearing  and  the  wearing  away 
of  the  bolt  holes. 

Don't  think  that  because  your  shafting  has  been  well 
erected  and  you  oil  it  regularly,  that  it  will  never  need  any 
inspection  or  repairs. 

Don't  try  to  economize  in  first  cost  by  having  long  dis- 
tances between  hangers,  for  a  well  supported  shaft  will 
always  do  the  best  work  ;  short  shafts  are  the  surest  to  be 
straight  and  to  remain  so,  ( 

The  length  usually  adopted  for  shafting  bearings  is  twice 
to  four  times  the  diameter  of  the  shaft,  varying  with  the 
diameters  of  shaft,  kind  of  bearings  and  the  material  used  in 
them.  Large  shafts-  in  the  gun-metal  or  bronze  boxes  may 
have  bearings  only  twice  theii  diameter  in  length.  Cast  iron 
bearings  up  to  and  including  three  inch  shafts  are  often  made 
four  diameters  of  the  shaft  in  length,  particularly  for  self- 
adjusting  hangers. 

If  Babbit  is  used  for  the  boxes,  use  only  a  good  metal; 
do  not  adopt  the  common  mixture  of  tin,  antimony  and 
lead. 

Insist  upon  having  good  iron  in  your  shafting,  as  the 
bearings  will  take  a  finer  polish,  and  you  will  not  be  subject 
to  sudden  ruptures. 

If  the  strain  on  a  pulley  is  so  great  that  the  set-screws 
already  in  will  not  hold  it,  d'o  not  let  them  score  into  the 
shaft,  but  put  in  an  extra  screw,  or  cut  a  key- way  and  put  in 
a  key.  « 

The  width  of  a  key-way  should  be  one-quarter  of  an  inch 
fort^Ci*  inch  of  diameter  of  the  shaft. 

The  depth  of  a  key-way  is  one-half  its  width. 


322 
WORKSHOP  JOTTINGS. 

To  Prepare  Zinc  for  Put  tiling — Apply  sulphuric  acid 
and  water  for  a  quarter  of  an  hour  ;  then  wash  off  clean  with 
water  and  dry. 

Moisture-Resisting  Glue — A  glue  which  is  proof  againsj 
moisture  may  be  made  by  dissolving  16  ounces  of  glue  in  3 
pinte  of  skim  milk.  If  a  stronger  glue  be  wanted,  add 
powdered  lime. 

A  Good  Lubricator — It  may  not  be  generally  known  that 
tallow  and  plumbago  thoroughly  mixed  make  the  best  lubri. 
cator  for  surfaces  when  one  is  wood  or  when  both  are  wood. 
Oil  is  not  so  good  as  tallow  to  mix  with  plumbago  for  the 
lubrication  of  wooden  surfaces,  because  oil  penetrates  and 
saturates  the  wood  to  a  greater  degree  than  tallow,  causing  it 
to  swell  more. 

To  Prevent  Metals  jRusttng—The  following  is  said  to 
be  a  good  application  to  prevent  metals  rusting :  Melt  I  oz. 
of  resin  in  a  gill  of  linseed  oil,  and  while  hot  mix  with  it  two 
quarts  of  kerosene  oil.  This  can  be  kept  ready  to  apply  at 
any  time  with  a  brush  or  rag  to  any  tools  or  implements 
required  to  lay  by  for  a  time,  preventing  any  rust,  and  saving 
much  vexation  when  the  tool  is  to  be  used  again. 

7*o  Prei>ent  Slipping  of  Belts — Belts  conveying  power 
are  very  apt  to  slip  on  pulleys,  but  a  new  pulley  has  been 
devised  to  prevent  this.  The  pulley  is  covered  with  per- 
forated sheet  iron  one-sixteenth  of  an  inch  thick,  which  is 
riveted  to  the  pulley.  The  tension  of  the  belt  causes  it  to 
grip  slightly  the  holes,  and  thus  slipping  is  avoided,  while  at 
the  same  time  the  pulley  is  strengthened. 

To  Calculate  Water  in  a  Pipe — To  calculate  roughly  the 
quantity  of  water  in  any  given  pipe  or  other  cylindrical  ves- 
sel, it  is  only  necessary  to  remember  that  a  pipe  one  yard,  or 
three  feet,  long  will  hold  about  as  many  pounds  of  water  as 
the  square  of  its  diameter  in  inches.  Thus:  If  we  have  a 
pipe  20  inches  in  diameter  and  16  feet  long,  we  have  simply 
to  square  20  (2O2— 400),  and  multiply  the  result  by  the 
number  of  times  3  feet  is  contained  in  16  feet=5X  times; 
hence,  400x5^=2,133  pounds.  By  increasing  the  result  by 
2  per  cent.,  or  i-5Oth,  a  more  nearly  exact  figure  can  be 
obtained. 


323 
BRASS  AND  ITS  TREATMENT. 

Brass,  as  previously  stated,  is  perhaps  the  best  known  and 
most  useful  alloy.  It  is  formed  by  fusing  together  copper  ^ 
and  zinc.  Different  proportions  of  these  metals  produce 
brasses  possessing  very  marked  distinctive  properties.  The 
portions  of  the  different  ingredients  are  seldom  precisely  alike; 
these  depend  upon  the  requirements  of  various  uses  for  which 
the  alloys  are  intended.  Peculiar  qualities  of  the  constituent 
metals  also  exercise  considerable  influence  on  the  results. 

Brass  is  fabled  to  hivebeen  first  accidental'y  formed  at  the 
burning  of  Corinth,  146  B.  C,  but  articles  of  brass  have  been 
discovered  in  the  Egyptian  tombs,  which  prove  it  to  have  had 
a  much  greater  antiquity.  Brass  was  known  to  the  ancients 
as  a  more  valuable  kind  of  copper.  The  yellow  color  was  con- 
sidered a  natural  quality,  and  was  not  supposed  to  indicate  an 
alloy.  Certain  mines  were  much  valued,  as  they  yielded  this 
gold-colored  copper,  but  after  a  time  it  was  found  that  by 
melting  copper  with  a  certain  earth  (calamine),  the  copper 
was  changed  in  color.  The  nature  of  the  change  was  still 
unsuspected. 

Alloy  of  copper  and  zinc  retain  their  malleability  and 
ductility  when  the  zinc  is  not  above  33  to  40  per.  cent,  of  the 
alloy.  When  the  zinc  is  in  excess  of  this,  crystalline  character 
begins  to  prevail.  An  alloy  of  one  copper  to  two  zinc  may 
be  crumbled  in  a  mortar  when  cold. 

Yellow  brass  that  files  and  turns  well  may  consist  of  cop- 
per 4,  zinc  i  to  2.  A  greater  proportion  of  zinc  makes  it 
harder  and  less  tractable;  with  less  zinc  it  is  more  tenacious 
and  hangs  to  the  file  like  copper.  Yellow  brass  (copper  2, 
zinc  i)  is  hardened  by  the  addition  of  two  to  three  per  cent, 
of  tin,  or  made  more  malleable  by  the  same  proportion  of 
lead. 

There  would  be  less  diversity  in  the  results  of  brass  cast- 
ings if  what  was  put  in  a  crucible  came  out  of  it.  The  vola- 
tility of  some  metals,  and  the  varied  melting  points  of  others 
in  the  same  mix,  greatly  interfere  with  the  uniformity  in 
ordinary  work.  Zinc  sublimes  (burns  away)  at  773  to  800 
degrees,  while  the  melting  heat  of  the  copper  —  with  which  it 
should  be  intimately  mixed  in  making  brass — is  nearly  1,750 
degrees.  Copper,  zinc,  tin  and  lead  in  varying  proportions 
form  alloys,  always  in  definite  quantity  for  a  given  alloy. 
The  ease  with  which  some  of  the  metals  are  burned  away  at 
comparatively  low  temperatures  renders  it  a  very  easy  mat- 
ter to  make  several  different  kinds  of  metal  with*the  same 
mix.  T  nls  very  thing  occurs,  and  the  great  difficulty  in  get. 


324 

ting  bearing  brasses  uniform  in  quality  causes  some  engineers 
to  babbitt  all  bearings  as  the  best  way  to  insure  uniformity. 
One  lot  of  castings  may  VJe  soft  and  tough,  another  hard,-' 
and  so  on.    ^ 

Zinc  is  added  the  last  thing  as  the  crucible  comes  out  of 
the  furnace,  and  the  mixing  of  the  mass  is  a  matter  of  uncer- 
tainty. If  the  metal  Is  too  hot  for  the  zinc  a  large  percent- 
age goes  off  in  the  form  of  a  greenish  cloud  of  vapor,  and 
the  longer  the  stirring  goes  on  the  more  escapes.  The  two 
metals  which  enter  into  the  composition  of  brass  have  an 
affinity  for  each  other,  but  they  must  be  brought  into  inti- 
mate contact  before  they  will  combine.  Some  brass  founders 
use  precautions  to  prevent  volatilization  of  the  more  fusible 
metals,  introducing  them  under  a  cover  }f  powdered  charcoal 
on  top  of  the  copper. 

"  Brass  finisher "  is  a  term  many  understand  as  applied 
only  to  those  who  produce  highly-finished  brass  work  ;  but  it  is 
not  so  ;  the  brass  finisher's  work  is  not  the  superior  class  of 
work  supposed,  most  of  it  toing  comprised  in  gas  fittings, 
ormolu  mounts,  etc.,  but  the  Highest  class  of  brass  finishing 
is  a  totally  different  process.  Fittings  for  gas  work,  all 
finished  well  enough  for  their  several  purposes,  and  as  well 
done  as  the  price  paid  for  them  will  allow,  as  well  as  the 
mountings  for  furniture,  must  obviously  be  produced  at  a  lo\\ 
price,  in  order  to  supply  the  demand  for  cheap  work  of  this 
character,  most  of  which  is  simply  dipping,  burnishing  and 
lacquering. 

Let  us  follow  the  process  of  finishing  the  highest  class  of 
brass  work.  Before  commencing  to  polish,  all  marks  of  the 
file  must  be  removed,  and  this  is  clone  thus  :  Having  used  a 
superfine  Lancashire  file  to  smooth  both  the  edges  and  surfaces, 
take  a  piece  of  moderately  fine  emery  paper  and  wrap  it 
tightly,  once  only,  round  the  file.  By  having  many  folds 
round'  the  file  the  work  becomes  rounded  at  the  edges, 
and  so  made  to  look  like  second-rate  things.  Some  use 
emery  sticks,  made  of  pieces  of  planed  wood  about  ft 
inch  thick  and  ^  inch  wide,  quite  flat  on  the  surfaces. 
They  are  covered  with  thin  glue,  and  the  emery  powdered  onto 
them,  and  then  allowed  to  dry  hard.  Most  common  work 
is  rubbed  over,  not  to  say  finished,  with  emery  cloth.  This 
will  not  do  for  good  work.  The  paper  folded  once  round 
the  file  is  used  in  a  similar  manner  to  the  file,  and  when  the 
file-marks  disappear,  and  the  paper  is  worn,  a  little  oil  is 
used,  which  makes  it  cut  smoother.  Tphe  edges  and  surfaces 
being  prepared  to  this  extent,  tite  cjges  must  be  finished. 
To  effect  this  take  a  piece  of  flat,  soft  wood,  and  apply  t  >  its 


325 

surface  a  little  fine  oil-stone  powder;  be  sure  that,  it  is  quite 
clean,  as  it  is  very  annoying  to  make  a  deep  scratch  in  the 
work  just  as  it  is  finished;  perhaps  so  deep  that  it -will  re- 
quire filing  out. 

FACTS  ABOUT  A  WATCH. 

The  watch  carried  by  the  average  man  is  composed  of 
ninety  eight  pieces,  and  its  manufacture  embraces  more 
than  2,000  distinct  and  separate  operations.  Some  of  the 
smaller  screws  are  so  minute  that  the  unaided  eye  cannot 
distinguish  them  from  steel  filing  or  specks  of  dirt.  Under 
a  magnifying  glass  a  perfect  screw  is  revealed.  The  slit  in 
the  head  is  two  one-thousandths  of  an  inch  wide.  It  takes 
308.000  of  these  screws  to  weigh  a  pound,  and  a  pound  is 
worth  $1,585.  The  hairspring  is  a  strip  of  the  finest  steel, 
about  9l/z  inches  long,  and  one-hundredth  inch  wide  and 
twenty-seven  ten-thousandths  inch  thick.  It  is  coiled  up  in 
a  spiral  form  and  finely  tempered. 

The  process  of  tempering  these  springs  was  long  held  us  a 
secret  by  the  few  fortunate  ones  possessing  it,  and  even  now 
it  is  not  generally  known.  Their  manufacture  requires 
great  skill  and  care.  The  strip  is  gauged  to  twenty  one- 
thousandths  of  an  inch,  but  no  measuring  instrument  has 
yet  been  devised  capable  of  fine  enough  gauging  to  deter- 
mine beforehand  by  the  size  of  the  strip  what  the  strength 
of  the  finished  spring  will  be.  A  twenty  one-thousandth 
part  of  an  inch  difference  in  the  thickness  of  the  stop  makes 
a  difference  in  the  running  of  a  watch  of  about  six  minutes 
an  hour. 

The  value  of  these  springs,  when  finished  and  placed  in 
watches,  is  enormous  in  proportion  to  the  material  from 
which  they  are  made.  A  comparison  will  give  a  good  idea. 
A  ton  of  steel  made  up  into  hairsprings  when  in  watches  is 
worth  more  than  12^  times  the  value  of  the  same  weight  in 
pure  e-old.  Hairspring  wire  weighs  1-20  of  a  grain  to  an 
inch.  One  mile  of  wire  weighs  less  than  half  a  pound.  The 
balance  gives  five  vibrations  every  second,  300  every  min- 
ute, 18,000  every  hour.  432,000  every  day  and  157,680,000 
every  year.  At  each  vibration  it  rotates  about  1*4  times, 
which  makes  197.100,000  revolutions  every  year. 

In  order  that  we  may  better  Understand  the  ^stupendous 
amount  of  labor  nerformed  by  these  tiny  works,  let  us  make 
a  pertinent  comparison.  Take,  for  instance,  a  locomotive 
with  six-foot  driving  wheels.  Let  its  wheels  be  run  until 
they  have  given  the  same  number  of  revolutions  that  a 
watch  does  in  one  year,  and  they  will  have  covered  a  dis- 
tance equal  to  28  complete  circuits  of  the  earth.  All  this  a 
watch  does  without  other  attention  than  winding  once  every 
24  hours. 


Fig.  i. 


326 
METAL- WORKING   DIES   AND  THEIR   USES. 

BY   HENRY   LONG. 

In  the  following  pages,  which  have  been  specially  prepared 
for  this  work,  will  be  found  a  condensed  description  of  the 
commoner  kinds  of  dies  now  in  use  for  sheet-metal  work. 
There  being  several  kinds  of  punching  presses,  I  will  specify 
the  variety  in  which  each  die  can  be  used  as  I  describe  it. 
The  commonest  in  use  is  the  simple  cutting-die,  and  I  will 
describe  it  first.  It  can  either 
be  made  by  welding  a  steel  ring 
of  the  shape  desired  on  a 
wrought  iron  plate,  and  then 
dressing  the  hole  out  roughly 
to  pattern  while  hot,  or  by 
drilling  out  a  hole  of  the  shape 
required  through  a  piece  of 
flat  steel  of  proper  dimensions, 
i  and  then  dressing  it  out  with 
'  files,  etc.,  to  exact  size.  While 
the  former  plan  is  most  expen- 
sive, it  is  the  best  in  regard  to 
wear  and  quality  of  work.  Fig.  i  represents  a  die  of  this 
kind.  The  forging  for  this  die  would  be  made  as  I  explained 
above;  that  is,  by  welding  a  steel  ring  of  the  shape  of 
the  pattern  on  an  iron  plate,  and  cutting  the  hole 
through  the  iron  afterward.  The  punch  for  this  would  be 
made  simi'arly,  only,  that  the  ring  is  the  shape  of  pattern 
outside,  and  after  welding  to  the  iron  plate  it  is  trimmed  off 
outside.  There  is  also  a  shank  to  be  welded  on  the  other  side 
of  plate,  as  nearly  central  as  possible,  and  large  enough  to 
finish  up  easily  to  size  required.  In  making  this  die  the  two 
faces  are  planed  off  clean,  and  then  the  pattern  is  laid  on  top 
face  and  the  die  is  marked  from  it.  When  this  is  done,  it  is 
put  in  the  shaper  and  planed  out  to  the  marks,  care  being 
taken  to  throw  the  work  forward  in  the  chuck  to  give  about 
/g-  in.  clearance  to  the  inch,  in  depth. 

It  is  now  filed  out  and  champfered  off  on  face,  as  shown, 
iffe  face  being  hollowed  out  jg"  on  three  or  four  sides  after- 
ward to  give  it  a  shearing  edge.  It  is  now  ready  for  tempering. 
As  the  tempering  requires  great  care  it  is  very  necessary  to 
watch  your  heat  closely,  and  while  making  it  even,  do  not 
heat  any  higher  than  necessary,  and  plunge  it  carefully  into 
cold  soft  water  with  one  edge  down,  keeping  it  in  there  until 
perfectly  cold.  Now  take  it  out  and  polish  the  face  and 
inside  well,  and  reheat  very  evenly  as  before  until  you  observe 


327 

a  dark  stra\v  color,  when  you  can  cool  it  off,  as  that  is  con- 
sidered a  good  temper,  and  one  that  will  stand  wear  without 
breaking.  The  punch  is  pared  off  on  both  sides  and  shank 
turned  up  to  size,  and  then  the  die  is  laid  on  it  face  to  face 
and  the  shape  marked  out.  Now  it  is  shaped  off  to  the  lines 
and  fitted  closely  in  the  die,  the  inside  edge  of  punch  being 
afterward  champfered  off  as  shown.  This  die  can  be  used  in 
any  press,  and  is  particularly  designed  ior  light  metals  such 
'as  zinc,  tin,  etc.  A  flat-cutting  die  would  be  made  by  taking 
a  piece  cut  from  the  bar  at  least  i%"  longer  and 
wider  than  your  pattern,  and,  after  planing  it,  lay 


your   pattern    on    and 
inside   the    marks    r.n  I 


Fig.  2. 


mark  the  hole.  Then  drill  around 
file  out  in  same  wray  as  you  do 
the  other.  The  punch  would  be 
made  same  as  last,  but  without 
champfering  off  the  edge.  This  die 
can  be  used  in  any  press,  and  is 
designed  for  heavy  work,  such  as 
hard  brass,  steel,  etc.  Sometimes 
there  may  be  some  narrow  or  weak 
part  in  the  die  which  is  likely  to 
break  out  in  time,  in  which  case  it  is 
economical  to  insert  a  plug  as  shown 
in  Fig.  2.  Of  course  these  plugs 
can  be  renewed  as  often  as  necessary  without  disturbing 
the  form  of  the  die.  For  round  holes  of  small  size,  a  steel 
plug  is  fitted  in  a  soft  steel  plate,  and  the  hole  drilled  and 
reamed  through  it,  after  which  the  plug  is  tempered. 

The  punch  is  simply  a  socket  with  a  set  screw  in  which 
round  steel  of  the  right  size  is  used,  in  this  way  saving  any 
turn  ins:  or  fitting.  Sometimes  a  gang  of  punches  is  used,  as 
,  for  which  a  special  punch  is  designed,  In 
this,  the  shank  is  a  separate  pieoe,-and 
has  a  dove-tailed  groove  planed  through 
it.  This  groove  should  be  from  fa"  to 
Yt"  larger  in  every  way  than  the  dimen- 
sions you  wish  to  punch.  It  should  also 
have^1,"  draft,  or  taper  endwise  to  allow 
of  a  driving  bit  on  the  plate  fitted  in. 
This  plate  should  be  YZ"  thick  at  least. 
You  first  drill  all  the  holes  in  your  die 
in  the  right  position,  and  after  reaming 
them  our,  harden  and  temper  it.  You 
now  place  this  plate,  which  you  have  fitted  in  the  shank,  on 
the  face  of  the  die  in  its  true  position  and  fasten  it  securely 
there.  The  next  thing  is  to  run  the  drill  you  used  on  the 


is  shown  in  Fiq 


328 

die,  through  tne  die  holes,  and  mark  their  exact  position  on 
this  plate.  When  this  is  done,  remove  the  die  and  drill  the 
holes  through  from  these  marks,  and  countersink  them  from 
behind.  Now,  the  stripper  or  guide,  which  should  be  about 
ffi'  thick,  is  fastened  on  in  the  position  you  wish  it,  and 
marked  and  drilled  in  the  same  way.  The  wire  punches  are 
made  by  riveting  over  a  head  on  one  end  and  then  driving 
them  in  from  the  back,  afterward  filing  off  any  superfluous 
metal  which  extends  above  the  back.  When  you  have  made  a 
gauge  and  placed  it  under  the  stripper,  fastening  securely,  the 
die  will  be  finished. 

The  punches  should  be  filed  to  an  even  face,  and  then  hol- 
lowed out  a  little  to  give  more  ease  in  cutting.  All  the  dies 
mentioned  thus  far  can  be  used  in  any  ordinary  press.  We 
will  now  take  up  the  different  kinds  of  form- 
ing dies.  There  are  only  two  kinds,  half- 
round  and  square;  all  others  are  modifica- 
tions of  these-.  The  depth  of  a  half-round 
forming  die  should  be  two-thirds  of  the 
diameter  to  give  the  best  results,  and  the 
punch  should  go  down  into  the  groove  as 
shown  in  Fig.  4.  A  mandril  is  necessary  to 
form  the  work  over  in  the  die.  A  square 
or  box-forming  die  is  simply  a  square  hole 
of  the  right  size,  cut  through  the  die,  per- 
fectly parallel,  and  with  the  upper  corners 
rounded  a  little.  If  a  smooth  flat 
bottom  is  required  it  is  usual  to  make 
the  die  of  thinest  steel,  and  put  a  plate 
under  it  as  in  Fig.  5,  with  a  pad  and 
spring,  to  throw  it  out.  The  punch 
is  size  of  the  inside  of  box,  and  a  close 
fit.  A  die  for  forming  a  shape  at  any 
angle  is  simply  a  groove  planed  thro' 
the  block  and  having  a  punch  to  fit 
it.  Fig.  6  is  a  view  of  a  common 
form  of  drawing  die  for  deep  work. 
They  are  used  for  making  caps,  cart- 
ridge cases,  etc.  It  consists  of  a 
round  disk  of  steel  about  ^6  "deep 


Fig.  5- 


with  a  hole   the  size  of  shell  required  bored  in  it . 

%  This  hole  is  well  rounded  off  at  the  corner,  and  counter- 
bored  from  the  bottom  with  a  square,  sharp  shoulder  for 
stripping  the  work  off  the  punch  after  it  has  passed  through 
the  die.  A  cast-iron  holder  with  set  screw  is  generally  used 
with  these  dies  for  convenience  in-  changing.  The  punch  i& 


Fig.  6, 


329 

fitted  into  a  socket  in  the  shank  and  held  by 
a  set  screw.  It  is  rounded  on  the  corners  to 
give  the  metal  a  better  chance  to  turn  up 
around  it.  When  the  punch  and  die  are  set 
the  blank  is  laid  on  the  die,  and  the  punch 
should  be  tight  enough  to  carry  it  through 
without  a  wrinkle.  If  the  shell  is  not  long 
enough  after  this  operation,  make  a  die  a 
little  smaller  and  a  punch  the  same,  and  after 
annealing  the  shells  pass  them  through  it.  By 
repeating  this  operation  you  can  produce 
shells  of  almost  any  length.  Sometimes  it  is 
necessary  to  make  a  die  to  perform  some 


operation  on  the  edge  of  a  box  which  has  already  been  formed 
In  this  case  the  die  is  made  in  such  a  way  that  the  box  can 
be  put  on  it,  thus  placing  the  die  on  the 
inside.  A  hub  is  made  the  shape  of  the 
box,  and  with  the  die  dovetailed  into  its 
upper  side,  a  hole  being  bored  clown 
through  the  hub  to  allow  the  cuttings  to 
fall  through.  v  This  hub  is  fitted  into  a 
special  holder  as  shown.  The  punch  is 
made  in  the  same  way  as  others.  These 
dies  can  be  used  for  any  operation  that 
a  flat  die  performs,  such  as  cutting,  form- 
ing, etc.  As  I  have  given  a  description 
of  the  different  forms  of  simple  dies,  I  will  now  explain  some 
double  and  combination  dies.  A  double  die  is  two  distinct 
dies  in  one  plate,  and  it  may  be  extended  to  include  three 
or  four,  although  the  work  gets  complicated  in  this  case, 
and  the  economy  is  doubtful. 

This  die  may  be  composed 
of  two  cutting  dies,  or  one  cut- 
ting and  one  forming  die,  or,  in 
fact,  any  combination  which 
may  seem  desirable.  It  is  gen- 
erally used  for  cutting  dies, 
such  as  washers,  etc.  Fig.  8 
shows  the  plan  of  one  of  these 
dies  designed  to  make  a  washer. 
You  will  perceive  that  the  first 
punch  is  the  size  of  the  hole  in 
the  washer  and  the  second  cuts 
out  the  washer  itself.  The 
punches  are  set  in  a  long,  flat 
socket,  and  fastened  with  set 
screws.  The  main  point  in  these 


Fig.  8. 


dies  is  to  get  them  correctly  spaced  so  as  to  cut  out  all  the 
stock.  They  can  be  used  in  a  power  or  foot  press.  A.;com- 
bination  die  is  one  which  performs  two  or  more  operations  in 
one  die.  Fig.  9  is  one  of  these,  designed  to  make  a  black- 
ing-box cover.  In  this  die  the  pinch  comes  down  and  cuts 
out  the  blank  which  is 
immediately  gripped  be- 
tween the  two  face  a 
and  b,  and  held  firmly 
enough  to  p  r  e  v  cut 
wrinkling,  but  still  to 
allow  of  its  being  drawn 
through  and  over  the 
form  which  is  in  the 
center  of  the  die. 
When  tne  press  is  on  the 
return  stroke,  the  ring  b 
follows  the  punch  up  and  ' 
pushes  the  cover  off 
again,  while  the  pad  in 
the  punch  does  the  same 
there,  thus  having  the 
cover  loose  on  the  top 
of  the  die.  These  dies 


Fig-  io. 


Fig.  9. 

must  be  operated  in  a  power 
press,  or  one  specially  de- 
signed for  the  purpose,  and 
they  are  more  conveniently 
worked  .in  an  inclined  than 
a  horizontal  press,  as  the 
work  will  then  fall  off  by  the 
force  of  its  own  gravity. 

Fig.  10  is  a  die  of  the 
same  class,  but  with  another 
operation  added.  It  is  de- 
signed to  make  a  pepper-box 
cover,  and  perforates  four 
holes  in  it  after  it  is  drawn. 
The  punch, as  you  will  per- 
ceive, is  entirely  different  in 
its  construction.  -.The  die  is 
the  same,  excepting  that  four 
cutting  holes  •  or  dies  are 
drilled  in  the  top  of  the  form 


331 

or  plug,  and  the  inside  is  bored  out  to  allow  the  cuttings  to 
fall  through.  The  stub  is  also  bored  out  for  the  same  reason. 
In  the  punch  a  is  the  shank,  bored  out  as  shown,  b  is  the 
cutting  edge  or  punch  proper  ;  it  is  bored  or  chambered  out 
for  the  pad  c  to  work  in  it.  d  is  a  plate  that  screws  into  the 
top  of  the  punch  b,  to  act  as  a  back  for  the  pad  c  to  press 
against,  and  also  as  a  holder  for  the  four  small  punches.  It 
has  three  holes  in  it,  through  which  short  pins  work  to  com- 
municate the  power  of  spring  E  to  the  pad  c.  //is  a  washer 
under  the  spring,  and  G  is  a  plug  or  pin  that  screws  in  the  top 
of  shank,  and  extends  down  to  the  plate  d,  against  which 
it  presses,  in  this  way  hold- ing  the  small  pin  punches  down 
to  place,  and  guiding  and  regulating  the  spring  at  the  same 
time.  The  operation  of  the  die  is  the  same  as  Fig.  9,  only 
that  after  the  tin  has  been  drawn  down  its  full  length,  the 
small  punches  cut  the  holes  through  the  top,  and  then  the 
pad  c  acts  as  a  stripper  for  these  punches  at  the  same  time 
as  it  punches  the  cap  out  of  the  large  punch. 

As  all  other  combinations  are  made  on  this  plan,  it  is 
hardly  necessary  to  describe  any  others. 

Fig.  1 1  represents  a  die  for  doing  the  same  work,  but  in 
what  is  called  a  cam  or  double-action  press.     These  dies  are 

much  simpler  and 
cheaper  to  make  and 
do  equally  good  work 
with  the  others.  The 
piece  A  is  the  cutting 
punch,  and  works  in 
the  die  B.  After  cut- 
ting the  blank  it 
passes  down  until  it 
presses  the  blank 
against  the  face  shown 
on  the  inside  of  the 
die.  While  it  is  hold- 
ing the  blank  firmly 
there  the  fo  r  m  i  n  g 
cutting  punch 


yMMMwxvA 

I 


Fig.  11. 


punch    C    passes    down    through    the  _ 

forces  the  tin  down  through  the  inside  die  B,  in  this  way 
forming  it  into  any  shape  desired.  In  passing  up  again  it 
strips  the  box  off  against  the  underpart  of  the  die,  allowing  it 
to  fall  into  a  box  underneath.  This  covers  the  list  as  an- 
nounced in  the  beginning  of  this  article,  and  although  the 
different  kinds  of  dies  are  endless,  the  foregoing  description 
will  enable  the  reader  to  judge  of  the  best  way  of  doing  work, 
and  there  is  hardly  any  pattern  which  cannot  be  produced  by 
fme  or  more  of  these  dies  in  coiwbination. 


332 

RULE    TO    FIND    THE    STRENGTH   OF    BOILER 
SHELLS  AND  FLUES. 

The  pressure  for  any  dimension  of  boiler  can  be  ascertained 
ty  the  following  rule,  viz. : 

Multiply  one-sixtli  (^th)  of  the  lowest  tensile  strength 
found  stamped  on  any  plate  in  the  cylindrical  shell  by  the 
thickness — expressed  in  inches,  or  parts  of  an  inch — of  the 
thinnest  plate  in  the  same  cylindrical  shell,  and  divided  by  the 
radius  or  half  diameter  —  also  expressed  in  inches — and  the 
quotient  will  be  the  pressure  allowable  per  square  inch  of  sur- 
face for  single  riveting,  to  which  add  twenty  per  centum  for 
double  riveting. 

Boilers  built  prior  to  February  28,  1872,  shall  be  deemed 
to  have  a  tensile  strength  of  50,000  pounds  to  the  square  inch, 
whether  stamped  or  not. 

For  cylindrical  boileryfej-  over  16,  and  less  than  40  inches 
in  diameter,  the  following  formulas  shall  be  used  in  determin- 
ing the  pressure  allowable. 

Let  D  =  diameter  of  flue  in  inches. 
1760  =  A  constant. 

T  =  thickness  of  flue  in  decimals  of  an  inch. 
P  =  pressure  of  steam  allowable,  in  pounds. 
1760 

• =  F,  a  factor. 

D 

.31  =  C,  a  constant. 
FXT 

Formula  : =  P. 

C 

EXAMPLE, 

Given,  a  flue  20  inches  in  diameter,  and  .37  of  an  inch  in 
thickness  ;  what  pressure  could  be  allowed  by  the  inspectors? 
1760  88X.37 

F  = =  88  ;  then, =  105  +  pounds  as  the  allowa- 

20.  .31  ble  pressure. 

TO  CALCULATE  THE  SPEED  OF  A  BELT. 
To  find  the  speed  a  belt  is  traveling  per  minute,  multiply 
the  diameter  infect  of  either  pulley  by  3.7  times  its  revolutions 
per  minute  ;  the  result  is  the  feet  travel  of  belt  per  minute  if 
there  is  no  slip.  At  the  recent  "  Inventions  Exhibition  "  in 
Liverpool,  the  indicated  horse-power  transmitted  by  the  belt- 
ing averaged,  on  trial,  per  one  inch  width  of  belt  a  horse 
power,  a  speed  of  200  feet  per  minute  ;  it  would  seem  that  a 
liberal  factor  of  slip  should  be  allowed  outside  of  this. 


333 
SIZES  AND  WEIGHT  OF  SHEET  TIN. 


Mark. 


Xo.  of 
sheets 
in  Box. 


Dimensions. 


Length     |     Brdth. 


Wt. 

of 

Box. 


Inches.  Inches.          Lbs. 

1C 225               ntf  10  112 

IIC. 

IIIC i2#  9/2 

IX 13%  10  140 

IXX "                   "  "  161 

IXXX "  "  182 

IXXXX "                  •"  "  203 

DC loo               16^  12%  105 

DX ; "  "  26 

DXX 

DXXX 

DXXXX.... 

DC 200               15  ii 

DX... 

r     DXX 210 

r   DXXX....          «                   "  «  231 

?  DXXXX...          "  "  252 

jCW 225               13^  10 112 

The  following  table,  showing  the  number  of  pounds  per 
foot  in  various  woods,  in  different  stages  of  dryness : 

Shipping  Thoroughly    Kiln 

Green.       dry.  air  dried,     dried. 

White  ash 4%            4  3/2  24-5 

Gray  ash 4/2             3^  3  2l/4 

Birch $/2            4/2  4  3/2    ' 

Basswood 3^            3  2^  2^ 

Cottonwood 3^            3  2%  2% 

Cherry 5                4/2  3/2  3 

Chestnut 41A          '  3/2  2H  2% 

Soft  elm 4                3/2  3 

Rock  elm 5                4%.  3^  Z1A 

Hickory 5^             4^  4  31A 

Hard  maple S/4            4/4  3^  3 

Bird's-eye    maple ....  5j^             4%  3M  3 

Curly  maple 4$             4  3/4,  2^ 

White  oak 6                5  4/2  4 

Red  oak 5^2             4/4  3/4  3 

Sycamore 5                 4  3  2^ 

Walnut 6                5  4  3^ 

Whitewood 4>2             31A  2H  2/^ 


334 


CALIBER    AND    WEIGHTS    OF    LEAD    PIPES. 


CALIBER. 

WEIGHT 
PER 
FOOT. 

CALIBER. 

WEIGHT 
PER 
FOOT. 

^  in.  tubing  

LBS. 

I 
I 

2 

2 

oz. 

6 

8 

12 

8 
10 

12 

4 

12 

s  . 

\l/2.  in.  aqueduct.  .  . 
ex.  light  

LBS.     OZ. 

3        8 

4 

i 

7        8 
3       12 
4        8 
5        8 
6        8 
8 
3 
4 

7        8 

8 

I 

n 
H 
17 
5 
9 

12 

16 

20 
15 

18 

21 

16 

21 

25 

36 

8 

y%  in.  aqueduct  .... 
light  

light 

medium  
strong  .  . 

medium  
strong. 

ex.  strong.  .  . 
J^  in.  aqueduct  .  .  .  . 
ex.  light  
lio-ht         .... 

ex.  strong.  .  . 
1  34  in.  light  .    .    ... 

light    

medium 

medium  .... 
strong 

strong  

ex.  strong..  .  . 
2  in.  wastf  . 

ex.  stron  r   .  . 

j^j  in.  aqueduct  
ex.  light  
light    ... 

2 
2 

3 
I 

2 
2 

3 

3 

i 

2 
2 
I 
2 
2 

3 
4 
4 

2 
2 

3 
3 
4 
6 

12 

4 

12 

8 

S 
4  i 

8 

8 
8 

8 
4 

12 

8 

12 
12 

2  in.  ex.  light  
light 

medium  
strong  

medium  
strong  
ex.  strong.  .  . 
$£  in.   aqueduct  .... 
ex.  light. 

ex.  strong.  .  . 
2  '2  in.  3-16  thick.  . 
14  thick  
5-16  thick.  .  . 
y%  thick. 

li<rht  .. 

medium  

3    in.    waste    

strong  

3  16  thick... 
%  thick 

ex.  strong  .  .  . 
fa  in.  aqueduct  .... 
ex.  light  

5-16  thick.  .  . 
y%  thick  
3  *A  in.  %  thick  .... 
5-16  thick..  . 
y%  thick 

light    . 

I  in.  aqueduct  
ex.  light  
light  

4   in.   waste  

medium. 

%  thick  

strong  

5-16  thick.  .  . 
y%  thick  

ex.  strong.  .  . 
lj£  in.  aqueduct...  . 
ex.  light  

7-16  thick.  .  . 
4^2  in.  waste  

5  tn.  waste  ..,.,... 

medium  
Strong 

ex.  strong.  .  . 

WEIGHT    OF    CIRCULAR    BOILER   HEADS. 


Diam. 
in 
inches. 

Thickness  of  Iron.  —  Inches. 

3-16 

X 

5-16 

H 

7-16 

X 

9-16 

16 

ii 

H 

18 

21 

25 

28 

32 

18 

!3 

18 

22 

27 

3i 

36 

40 

20 

17 

22 

27    33 

33 

44 

50 

22 

20 

27 

33  !   40 

47 

54 

60 

24 

24 

32 

40 

47 

55 

64 

7i 

26 

28 

37 

46 

56 

64 

75 

84 

28 

32 

43 

53 

65 

75 

86 

97 

3° 

37 

5° 

62 

74 

87 

100 

112 

32 

42 

56 

70 

84 

99 

112 

127 

34 

48 

64 

79 

96 

in 

128 

H3 

36 

54 

7i 

89 

1  08 

125 

I42 

161 

38 

60 

79 

99 

120 

139 

158 

179 

40 

66 

88 

HO 

132 

154 

I76 

198 

42 

73 

97 

121 

146 

170 

194  ' 

220 

44 

80 

107 

J33 

1  60 

187 

214 

740 

46 

88 

117 

H5 

176 

204 

234 

^62 

48 

95 

127 

158 

190 

222 

254 

286 

50 

103 

138 

172 

206 

241 

276 

310 

52 

112 

149 

1  86 

224 

260 

298 

335 

54 

121 

160 

200 

242 

28l 

320 

362 

56 

I30 

172 

214 

260 

302 

344 

389 

58 

139 

185 

231 

278 

324 

370 

4i7 

60 

149 

198 

247 

298 

336 

396 

446 

HOW    TO    CALCULATE    THE    CAPACITY   OF 

TANKS. 

In  circular  tanks,  every  foot  of  depth,  five  feet  diameter, 
gives  4^2  barrels  of  31^  gallons  each;  six  feet  diameter,  6}£ 
barrels;  seven  feet  diameter,  9  barrels;  eight  feet  diameter, 
12  barrels;  nine  feet  diameter,  15  barrels;  ten  feet  diameter* 
18^  barrels.  In  the  case  of  square  tanks,  for  every  foot  of 
depth  5  feet  by  5  feet  gives  6  barre.s ;  6  by  6  feet,  8 ] <  bar- 
rels; 7  by  7  feet,  n)4  barrels;  8  by  8  feet,  I  ~ T^  barrels  ;  9 
by  9  feet,  19^  barrels;  10  by  lo  feet,  23 -V  barrel. 


NUMBER  OK  BOILER    KIVKTS    IN  A   100   POUND 
KEG. 


Length. 

/^ 
Inch. 

9-16 

Inch. 

H 

Inch. 

11-16 
Inch. 

;X 

Inch. 

7/8 

Inch. 

990 

760 

56; 

450 

H 

875 

725 

530 

415 

X 

800 

690 

490 

389 

356 

228 

H 

760 

650 

460 

370 

329 

211 

'/2 

730 

625 

425 

357 

290 

i  So 

1% 

710 

595 

505 

340 

271 

174 

i% 

690 

550 

39° 

325 

264 

169 

1% 

665 

530 

375 

312 

257 

165 

2 

630 

5io 

360 

297 

248 

156 

2l/S 

590 

500 

354 

289 

237 

152 

2% 

555 

490 

347 

280 

232 

149 

2l/2 

525 

475 

335 

260 

219 

141 

*% 

500 

440 

312 

242 

211 

133 

3 

460 

AID 

290 

224 

203 

127 

3X 

430 

380 

267 

212 

I9O 

US 

3% 

410 

350 

248 

2O  I 

1  80 

108 

zH 

395 

335 

241 

I92 

l62 

102 

4 

326 

230 

184 

158 

99 

4>4 

312 

220 

177 

150 

96 

4^ 

298 

2IO 

171 

146 

94 

4# 

284 

2OO 

166 

138 

89 

5 

270 

190 

161 

135 

87 

SX 

256 

1  80 

156 

130 

84 

5^ 

244 

172 

*5i 

124 

80 

5^ 

233 

164 

H5 

I  2O 

77 

6 

223 

157 

140 

"5 

74 

6# 

213 

150 

137 

in 

71 

6 

207 

146 

134 

107 

69 

6 

203 

H3 

129 

104 

67 

7 

i)8 

I4O 

125 

100 

64 

To  BRONZE  IRON  CASTINGS.— After  having  thoroughly 
cleaned  the  castings,  immerse  them  in  a  solution  of  sulphate 
of  copper.  The  castings  will  then  take  on  a  coaHng  of  cop- 
per. Then  wash  thoroughly  in  water. 


Copper  is  said  to  lose  18  per  cent,   of  its  tenacity  upon 
being  raised  from  60°  to  36o9. 


337 

NUMBER    OK     "  AMERICAN" "    NAILS     AND    CUT 
SPIKES  IN  A  POUND. 


.s  ^ 

g 

bi> 

<u 

0 

e 

CJ 

fcJD 

.S 

'cL 

g  J5 

.'2 

5 

G 

r<v 

rt 

S 

'S 

£ 

^: 

u 

£ 

U 

2  F 

1050 

1/g 

3  1' 

860 

2 

900 

jif 

3 

500 

650 

670 

4 

300 

480 

45° 

500 

3^ 

5 

212 

350 

300 

370 

2 

6 

160 

85 

240 

212 

260 

2X 

7 

135 

65 

190 

1  60 

210 

2/^> 

8 

95 

50 

135 

120 

155 

234: 

9 

75 

40 

3 

10 

60 

35 

"5 

IOO 

135 

16 

3X 

12 

48 

30 

IOO 

120 

16 

34 

25 

80 

IOO 

H 

4'r 

20 

24 

20 

65 

85 

12 

30 

18 

50 

70 

IO 

5r 

40 

15 

40 

60 

9 

50 

12 

8 

6  2 

»y 

60 

10 

6 

| 

4 

Clinch-nails  weigh  about  the  same  as  common. 

Box-nails  are  made  ^  inch  shorter  than  common  nails  of 
same  sizes. 

5  Ibs.  of  4d  or  3^  Ibs.  of  3d  will  lay  i,oop  shingles.  5^ 
Ibs.  of  3d  fine  will  put  on  1,000  laths,  four  nails  to  the  lath. 

Bricks  made  from  the  refuse  of  slate  quarries  are  stronger 
than  stone;  they  stand  7,200  Ibs.  compression  against  6,000 
for  stone,  and  3,200  Ibs.  for  common  brick.  The  cost  is  from 
$12  to  $20  per  thousand. 

In  London  20,000  men  earn  their  living  at  carpenter  work* 
4,000  in  Paris,  and  4,000  in  Berlin.     Hours  in  London  are 
per  week. 


33* 

WAXING    FLOORS. 

Take  a  pound  of  the  best  beeswax,  cut  it  up  into  very  small 
pieces,  and  let  it  thoroughly  dissolve  in  three  pints  of  turpen- 
tine, stirring  occasionally  if  necessary.  The  mixture  should 
be  only  a  trifle  thicker  than  the  clear  turpentine.  Apply  it 
with  a  ~ag  to  the  surface  of  the  floor,  which  should  be  smooth 
and  perfectly  clean.  This  is  the  difficult  part  of  the  work, 
for,  if  you  put  on  either  too  much  or  too  little,  a  good  polish 
will  be  impossible.  The  right  amount  varies,  less  being 
required  for  hard,  close-grained  wood,  and  more  if  the  wood 
is  soft  and  open-grained.  Even  professional  "waxers"are 
sometimes  obliged  to  experiment,  and  novices  should  always 
try  a  square^foot  or  two  first.  Put  on  what  you  think  will  be 
enough,  and  leave  the  place  untouched  and  unsteppecl  on  for 
twenty-four  hours,  or  longer  if  needful.  When  it  is  thor- 
oughly dry,  rub  it  with  a  hard  brush  until  it  shines.  If  it 
polishes  well,  repeat  the  process  over  the  entire  floor.  If  it 
does  not,  remove  the  wax  with  fins  sandpaper  and  try  again, 
using  more  or  less  than  before,  as  may  be  necessary,  and  con- 
tinuing your  experimenting  until  you  secure  the  desired  result. 
If  the  mixture  is  slow  in  drying,  add  a  little  of  any  of  the 
common  "dryers"  sold  by  paint  dealers,  japan  for  instance, 
in  the  proportion  of  one  part  of  the  drier  to  six  parts  of  tur- 
pentine. When  the  floor  is  a  large  one,  you  may  agreeably 
vary  the  tedious  work  of  polishing  by  strapping  a  brush  to 
each  foot  and  skating  over  it. 

HOW  TO  MAKE  AN  IVORY  GLOSS  ON  WOOD. 
A  most  attractive  ivory  gloss  is  now  imparted  to  wood 
surfaces  by  means  of  a  simple  process  with  varnish,  the  latter 
being  of  two  kinds,  namely,  one  a  solution  of  colorless  resin 
in  turpentine,  the  other  in  alcohol.  Eor  the  first,  the  purest 
copal  is  taken,  while  for  the  second  sixteen  parts  of  sandarac 
are  dissolved  in  sufficient  strong  alcohol,  to  which  are  added 
three  parts  of  camphor,  and  finally,  when  all  these  are  dis- 
solved, they  are  combined  with  five  parts  of  well-shaken 
Venice  turpentine.  In  order  to  insure  the  color  remaining 
a  pure  white,,  particular  care  is  essential  that  the  oil  be  not 
mixed  with  the  white  paint  previously  put  on.  The  be>t 
French  zinc  paint,  mixed  with  turpentine,  is  employee),  an  1, 
when  d,y,  this  is  rubbed  down  with  sandpaper,  following 
which  the  varnish  described  is  applied 


339 
CARE  OK  OAK  LUMBER. 

Throughout  the  civilized  world,  except  in  extremely  hot 
fountries,  one  or  more  species  of  the  oak  is  found.  In  this 
country  oak  forests  abound  in  almost  all  the  Southern  and 
Cerrtral  States.  In  species  there  are  so  many  that  even 
experienced  lumbermen  are  frequently  perplexed  to  correctly 
designate  to  which  class  a  sample  piece  of  wood  belongs. 
Ordinarily  in  the  yard  trade  but  two  kinds  are  known — 
white  and  red.  Among  shipbuilders,  carriage-makers  and 
machinists  may  be  found  live  oak,  a  species  of  wood  that  is 
peculiarly  adapted  to  purposes  where  immense  strength  is 
necessary.  The  average  lumberman,  when  he  talks  about 
white  oak  or  red  oak,  is  influenced  solely  by  the  color  of  the 
wood  when  it  becomes  partially  seasoned.  Again  and  again 
veterans  in  the  wood-working  business  have  been  known  to 
select  red  oak  for  white,  and  vice  versa  in  fact,  from  a 
dozen  specimens  of  six  different  species  of  oak,  they  have 
been  unable  to  correctly  name  a  single  sample.  f 

Oak  is  a  wood  •  which  calls  for  unusual  and  unceasing 
care  .in  its  manufacture.  The  tendency  of  oak,  from  the 
moment  an  ax  is  planted  in  the  side  of  the  tree,  is  to  split, 
crack,  and  play  all  sorts  of  mean  tricks  on  the  owner.  Such 
tendencies  can  be  held  in  hand,  and  almost  absolutely 
Dbviated,  by  following  certain  rules.  A  thick  coat  of  water- 
woof  paint  applied  to  the  ends  of  the  logs  is  a  wise  expendi- 
wre ;  it  prevents  the  absorption  of  moisture.  Oak,  when 
piled,  should  have  the  ends  protected  so  as  to  prevent  absorp 
tion  of  rain  and  moisture,  followed  by  the  baking  process  of 
a  hot  sun  Alternate  moisture  and  heat  is  the  prime  cause 
of  checks  and  cracks,  and  when  such  defects  begin  in  oak 
they  are  bound  to  increase  and  ruin  otherwise  perfect  stock. 

Oak  should  be  stuck  as  fast  as  sawed.  It  is  a  mistake  to 
permit  it  to  lie  in  a  dead  pile  even  for  a  single  day.  It  is  a 
wood  that  contains  a  large  amount  of  acid,  which  oozes  to  the 
surface  as  fast  as  the  lumber  is  sawed,  and,  if  the  stock  is 
allowed  to  remain  piled  solid,  it  is  apt,  even  in  a  few  hours, 
to  cause  stain  on  the  surface.  The  lumber  should  be  stuck 
in  piles  not  over  six  feet*  in  width.  The  bottom  course 
should  be  raised  two  feet  from  the  ground,  and  a  space  of  five 
mches  left  between  the  pieces.  It  is  advisable  to  follow  this 
rule  up  to  about  the  fifth  course,  when  tne  space  can  be 
gradually  diminished  to  two  inches,  and  continued  to  the  top 
of  the  pile!  In  this  way  air  has  free  circulation  through  the 
pile,  and  the  lumber  will  dry  readily.  The  pile  should  ca»t 
toward  the  back,  so  that  rain  will  fallow  the  inclination. 


340 

Board  sticks  not  over  three  inches  wide  should  be  used, 
the  front  stick  placed  so  as  to  project  a  half  inch  beyond  the 
lumber.  This  plan  permits  moisture  to  gather  in  the  stick, 
not  the  lumber.  Other  sticks  should  be  placed  not  over  four 
feet  apart,  and  in  building  the  pile  the  sticks  should  be 
exactly  over  one  another.  By  this  plan,  warps,  twists  and 
sags  are  avoided. 

Jt  is  advisable  to  pile  every  length  by  itself.  This  rule 
permits  more  systematic  piling,  and,  in  shipping,  consign- 
ments can  be  made  of  lengths  precisely  as  wanted.  Thick- 
nesses in  piling  should  never  be  mixed.  Twisted  stock  is 
certain  to  be  the  result  if  this  advice  is  ignored. 

The  sap  should  be  placed  downward.  The  draft  is  up- 
ward, and  any  practical  lumberman  can  readily  observe  trie 
advantage  of  this  advice.  Every  pile  should  be  well  covered 
with  sound  culls,  the  covering  so  placed  as  to  project  beyond 
all  sides  of  the  pile.  Raise  it  a  foot  from  the  top  course. 
The  piles  should  not  be  nearer  than  twenty  inches  apart; 
twenty-four  inches  is  better. 

HOW  TO  SHARPEN  A  PLANE-IP  ON. 

The  simple  art  of  sharpening  a  plane-iron  is  supposed  to 
be  understood  by  every  mechanic,  remarks  a  writer  in  a 
contemporary,  but  there  are  hundreds  of  men  who  cannot  do 
a  creditable  job  in  this  respect.  The  common  tendency  is  to 
round  off  the  edge  of  the  tool  until  it  gets  so  stunted  that 
under  a  part  of  the  cutting  the  tool  strikes  the  work  back  of 
the  cutting  edge.  To  do  the  job  correctly  we  will  begin  at 
the  beginning,  and  grind  the  tool  properly.  First,  the  kind 
of  wood  to  be  cut  must  be  taken  into  consideration.  Com- 
mon white  pine  can  best  be  worked  with  a  very  thin  tool, 
ground  down  even  t  >  an  angle  of  30  degrees,  provided  the 
make  of  the  tool  will  allo  ,v  it.  Some  planes  will  not,  for  the 
iron  stards  .so  "  stunt,"  or  nearly  perpendicular,  that  its  grind- 
ing causes  a  severe  scraping  action,  which  soon  wears  away  the 
tool.  In  such  cases,  from  45  to  60  degrees  is  the  proper 
angle  for  plane-iror»~  and  this,  too,  is  about  :ight  for  hard- 
wood planing.  .  3)  . 

Determine  the  angle  you  want  on  the  plane-iron  and  then 
grind  to  that  angle,  taking  care  to  grind  one  flat  bevel,  and 
not  work  up  a  dozen  facets.  If  the  stone  be  small,  say  12  to 
18  inches  in  diameter,  the  bevel  will  be  slightly  concave 
like  the  side  of  a  razor,  and  this  is  a  quality  highly  prized  by 
many  good  workmen.  In  grinding,  take  care  to  avoid  a 
"feather  edge."  If  the  tool  already  possesses  the  right 


341 

•hape,  grind  carefully  right  up  to  this  edge,  but  not  grinding 
it  entirely  off.  The  time  to  stop  grinding  a  tool  is  just  before 
the  old  bevel  is  ground  off. 

Should  the  tool  need  any  change  of  shape,  such  as  the 
grinding  out  of  a  nick  or  a  broken  place,  then  put  the  edge 
of  the  tool  against  the  stone  and  bring  the  tool  to  the  de- 
sired shape  before  touching  the  bevel. 

Let  the  iron  lay  perfectly  flat  upon  the  stone,  with  a 
tendency  only  to  bear  harder  upon  the  edge  of  the  bevel 
than  upon  the  heel.  Move  the  iron  back  and  forth  on  the 
stone  as  fast  as  your  skill  will  allow,  taking  care  that  the 
heel  of  the  bevel  is  not  lifted  from  the  stone.  As  you  be- 
come proficient  in  whetting  an  iron,  the  heel  may  be  lifted 
from  the  stone  about  the  thickness  of  a  sheet  of  paper,  or 
just  enough  to  prevent  it  from  touching.  The  reason  why 
many  carpenters  cannot  set  an  edge  is  because  they  raise 
their  hand  too  much,  and  perhaps  rock  the  tool,  thus  forming 
a  rounding  bevel,  the  sure  mark  of  a  poor  edge-setter.  ^ 

The  proper  way  to  oil-stone  a  tool  is  to  continue  the 
grinding  by  rubbing  on  the  oil-stone  until  the  bevel  left  by 
the  grindstone  is  entirely  moved  and  the  edge  keen  and 
sharp.  If  this  be  properly  done  the  tool  need  not  be  touched 
upon  its  face  to  the  stone,  but  among  a  dozen  good  edge- 
setters  not  more  than  one  can  do  it.  It  is  a  delicate  opera- 
tion, anil  can  only  be  acquired  by  long  practice.  Nine  times 
out  of  ten  the  average  workman  is  obliged  to  turn  the  plane- 
iron  over  and  wet  the  face  thereof,  and  here  is  where  many 
men  fail  who  have  done  the  other  things  well.  By  raising  the 
back  of  the  tool  only  a  very  little  the  edge  is  "dubbed  off," 
and  regrinding  of  the  face  becomes  an  immediate  necessity. 
A  good  stone  should  "  set  "  an  edge  on  a  tool  wh»  jh  will  shave 
off  the  hair  on  a  person's  wrist  without  cutting  the  skin  or 
missing  a  single  hair. 

VALUE  OF  MAHOGANY. 

As  is  known  to  every  woodworker,  mahogany  has  no 
equal  for  durability,  brilliancy,  and  intrinsic  value  for  any 
Work  which  requires  nicety  of  detail  and  elegance  of  finish. 
Cherry,  which  is  a  pretty  wood  for  effect,  and  extremely 
•leasing  when  first  finished,  soon  grows  dull  and  grimy- 
looking.  Oak,  which  has  been  so  much  used  of  late,  is 
attractive  when  first  finished,  but  experience  teaches  that  it 
does  not  take  many  months  to  change  all  this,  and  instead  of 
alight,  fresh  looking  interior,  one  that  has  a  dusty  appear- 
ance is  presented,  which  no  amount  of  scraping  ana  re- 


caking  will  restore  to  its  original  beauty.     What   applies  to 
in  this  yet  more  applicable  to  ash. 

Mahogany,  however,  seems  to  thrive  best  under  the  condi- 
tions which  are  detrimental  to  these  other  woods.  At  first 
of  a  light  tone,  it  grows  deeper  and  more  beautiful  in  color 
with  age,  and  although  its  first  cost  is  more  than  these  other 
woods,  yet  its  price  is  much  less  than  is  popularly  supposed ; 
#1 1  the  only  objection  urged  against  it  has  been  cost.  What 
is  more  valuable,  however,  and  what  makes  mahogany  in 
leality  a  less  costly  wood,  is  the  fact  that,  unlike  cherry,  oak 
f»r  ash,  it  is  easily  cleaned,  because  it  is  impervious  to  dust  or 
jb'rt,  while  it  does  not  show  wear,  and  instead  of  growing 
duller,  grows  brighter  and  more  pleasing  in  appearance. 
While  first  cost  is  more  than  that  of  cherry,  oak  or  ash,  it  is 
nevertheless  true  that  the  judgment  of  many  men  has  led 
tfiem  to  regard  mahogany  as  the  cheaper  wood  when  its  dura- 
bility and  cleanly  qualities  are  considered,  and  to-day  it  takes 
front  rank  in  first-class  material. 

POLISHING  GRANITE. 

The  form  is  given  to  the  stone  by  the  hands  of  skilled 
aiasons  in  much  the  same  way  as  is  done  with  other  stone  of 
ihfter  nature.  Of  course,  the  time  required  is  considerably 
greater  in  the  case  of  granite  as  compared  with  other  stones. 
If  the  surface  is  not  to  be  polished,  but  only  fine-axed,  as  it 
is  called,  that  is  done  by  the  use  of  a  hammer  composed  of  a 
number  of  slips  of  steel  of  about  a  sixteenth  of  an  inch  thick, 
which  are  tightly  bound  together,  the  edges  being  placed  on 
the  same  plane.  With  this  tool  the  workman  smooths  the 
surface  of  the  stone  by  a  series  of  taps  or  blows  given  at  a 
right  angle  to  the  surface  operated  upon.  By  this  means 
the  marks  of  the  blows  as  given  obliquely  on  the  surface  of 
the  stone  are  obliterated,  and  a  smooth  face  produced. 
Polishing  is  performed  by  rubbing,  in  the  first  place,  with 
an  iron  tool  and  with  sand  and  water.  Emery  is  next 
applied,  then  putty  with  flannel.  All  plain  surface  and 
molding  can  be  done  by  machinery,  but  all  carvings,  or  sur- 
faces broken  into  small  portions  of  various  elevations,  are 
done  by  the  hands  of  the  patient  hand-polishers. 

The  operation  of  sawing  a  block  of  granite  into  slabs  for 
panels,  tables  or  chimney-pieces  is  a  very  slow  process,  the 
rate  of  progress  being  about  half  an  inch  per  day  of  ten  hours. 
The  machines  employed  are  few  and  simple;  they  are  tech- 
nically called  lathes,  wagons  and  pendulums  or  rubbers.  The 
fethes  are  employed  for  the  polishing  of  columns,  the  wagons 


343 

for  flat  surfaces,  and  the  pendulums  for  molding^and  such  flat 
work  as  is  not  suitable  for  the  wagon.  In  the  lathe  fhe 
column  is  placed  and  supported  at  each  end  by  points  upon 
which  it  revolves.  On  the  upper  surface  of  the  column  there 
are  laid  pieces  of  iron  segments  of  the  circumference  of  the 
column.  The  weight  of  these  pieces  of  iron  lying  upon  the 
column,  and  the  constant  supply  of  the  lathe-attendant  of 
sand  and  water,  emery  or  putty,  according  to  the  state  of 
finish  to  which  the  column  lias  been  brought,  constitute  the 
m  whole  operation.  While  sand  is  used  during  the  rougher 
"  state  of  the  process  these  irons  are  bare,  but  when  using  emery 
and  putty,  the  surface  of  the  iron  next  to  the  stone  is  covered 
with  thick  flannel. 

The  wagon  is  a  carriage  running  upon  rails,  in  which  the 
pieces  of  stone  to  be  polished  are  fixed,  having  uppermost  the 
surface  to  be  operated  upon.  Above  this  surface  there  are 
shafts  plated  perpendicularly,  on  the  lower  end  of  which  are 
fixed  rings  of  iron.  These  rings  rest  upon  the  stone,  and 
when  the  shaft  revolves  they  rub  the  surface  of  the  stone.  At 
the  ^aiiie  time  the  wagon  travels  backward  and  forward 
upon  the  rails,  so  as  to  expose  the  whole  surface  of  the  stone 
to  the  action  of  the  rings.  The  pendulum  is  a  frame  hung 
upon  hinges  from  the  roof  of  the  workshop.  To  this  frame 
are  attached  iron  rods,  moving  in  a  Horizontal  direction.  ^In 
the  line  upon  which  these  rods  move,  and  under  them,  the 
stone  is  firmly  placed  upon  the  floor.  Pieces' of  iron  are  then 
loosely  attached  to  the  rods,  and  allowed  to  rest  upon  the  sur- 
face of  the  stone.  When  the  whole  is  set  in  motion,  these 
irons  are  dragged  backward  and  forward  over  the  surface  of 
the  stone,  and  so  it  is  polished.  When  polishing  plain  sur- 
faces, such  as  the  needle  of  an  obelisk,  the  pieces  of  iron  are 
flat ;  but  when  we  have  to  polish  a  molding,  we  make  an 
extra  pattern  of  its  form,  and  the  irons  are  cast  from  that 
pattern. 

IN  FAVOR  OF  SMALL  TIMBER. 

The  statement  that  a  12x12  inch  beam,  built  up  of  2x12 
planks  spiked  together,  is  stronger  than  a  12x12  inch  solid  tim- 
ber, will  strike  anovice  as  exceedingly  absurd.  An  authority 
on  the  subject  says  every  millwright  and  carpenter  knows  that  it 
is  so,  whether  he  ever  tested  it  by  actual  experience  or  not. 
The  inexperienced  will  fail  to  see  why  a  timber  will  be 
stronger  simply  because  the  adjacent  vertical  longitudinal 
portions  of  the  wood  have  been  separated  by  a  saw,,  and  if 
this  were  th:  only  thing  about  it,  it  would  not  be  stronger, 


344 

but  the  old  principle  that  a  chain  is  no  stronger  that  its 
weakest  link  comes  into  consideration.  Most  timbers  have 
knots  in  them,  or  are  sawed  at  an  angle  to  the  grain,  so  that 
they  will  split  diagonally  under  a  comparatively  light  load. 
In  a  built-up  timber  no  large  knots  can  weaken  the  beam 
except  so  much  of  it  as  is  composed  of  one  plank,  and  planks 
whose  grain  runs  diagonally  will  be  strengthened  by  the 
other  pieces  spiked  to  them. 

VALUABLE  ARTESfAN  WELLS. 

Two  artesian  wells  recently  sunk  in  Sonoma  Valley, 
Cal.,  are  considered  to  be  worth  not  less  than  $10.000  each. 
One  of  them  flows  90,000  gallons  of  water  per  day,  and  the 
other  100,000. 


The  cement  by  which  many  stone  buildings  in  Paris  have 
been  renovated  is  likely  to  prove  useful  in  preparing  the 
foundations  for  machinery.  The  powder  which  forms  the 
basis  of  the  cement  is  composed  of  two  parts  of  oxide  of 
zinc,  two  of  crushed  limestone  and  one  of  pulverized  grit, 
together  with  a  certain  proportion  of  ochre,  as  a  coloring 
agent-  The  liquid  with  which  this  powder  'is  to  be  mixed 
consists  of  a  saturated  solution  of  six  parts  of  zinc  in  com- 
mercial muriatic  acid,  to  which  is  added  one  part  of  sal-ammo- 
niac. This  solution  is  diluted  with  two-thirds  of  its  volume 
of  water.  A  mixture  of  one  pound  of  the  powder  to  two 
and  a  half  pints  of  the  liquid  forms  a  cement  which  hardens 
quickly,  and  is  of  great  strength. 

Large  cylinders  of  window-glass  are  now  cut  by  encircling 
the  cylinder  with  a  fine  wire,  which  is  then  heated  to  redness 
by  an  electric  current,  and  a  drop  of  water  being  allowed  to 
fall  upon  the  hot  glass  a  perfectly  clean  cut  is  obtained. 
The  old  method  was  to  draw  out  a  fiber  of  white-hot  semi- 
molten  glass  from  the  furnace  by  means  cf  tongs,  and  to 
wrap  it  round  the  cylinder. 

The  Hudson  Bay  Company,  which  was  incorporated  225 
years  ago,  is  the  oldest  incorporated  company. 

The  grindstone  quarries  along  the  shores  of  the  Bay  of 
Fundy  are  developed  when  the  tide  is  down.  The  best  ma- 
terial is  down  low  in  the  bay. 

Some  fine  pearls  were  recently  discovered  in  Tyrone  (Ire- 
land) rivets. 


345 


WOODEN    BEAMS. 

Safe    Load.  Uniformly    Distributed,    for   Rectan- 
gular  "White   or   Yellow    Pine  Beams  one  inch 
thick, 
allowing  1,200  Ibs.  per  square  inch  fibre  strain. 

To  obtain  the  safe  load  for  any  thickness,  multiply  the 
safe  load  given  in  table  by  the  thickness  of  beam. 

To  obtain  the  required  thickness  for  any  load,  divide 
by  the  safe  load  for  i  inch  given  in  table. 


i* 

DEPTH  OF  BEAM. 

6" 

7" 

8" 

9" 

10" 

11" 

12" 

13" 

14" 

16" 

16" 

r«t 

Ib, 

IbT 

Lbs. 

Lbe. 

LbL 

Lbs. 

Lbs. 

Lbs. 

Tfc. 

Lbs. 

Lbs. 

t£ 

960 

1810 

1710 

2160 

2670 

3230 

3840 

4510 

5230 

6000 

6830 

6 

800 

1090  i  1420 

180012220 

2690 

8200 

3760 

4860 

5000 

5690 

7 

690 

930 

1220 

1540 

1900 

2300 

2740 

3220 

8730 

4290 

4880 

8 

600 

820 

1070 

1850 

1670 

2020 

2400 

2820 

8270 

8750 

4270 

9 

530 

730 

950 

1200 

1480 

1790 

2130 

2500 

2900 

3330 

8790 

10 

480 

650 

850 

1080 

1880 

1610 

1920 

2250 

2610 

3000 

3410 

11 

440 

590 

780 

960 

1210  i  1470 

1750  2050 

2380 

&730 

3100 

12 

400 

540 

710 

900 

1110 

1340 

1600  1830 

2180 

2500 

2840 

18 

870 

500 

660 

830 

1030 

1240 

1480  i  1730 

£010 

2310 

2630 

14 

840 

470 

610 

770 

950 

1150 

1870 

1610 

1870 

2140 

2440 

15 

820 

440 

570 

780 

890 

r6so 

1280 

1500 

1740 

2000 

2280 

16 

300 

410 

530 

680 

830 

1010 

1200 

1410 

1630 

1880 

2130 

17 

280  880 

500 

640 

780 

950 

1130 

1330 

1540 

1760 

2010 

18 

270  860 

470 

600 

740 

900 

1070)1250 

1450 

1670 

1900 

19 

250  840 

450 

570 

700 

850  1  1010 

1190 

1380 

1580 

1800 

20 

240  1  830 

430 

540 

670 

810 

960 

1180 

1810 

1500 

1710 

21 

2801  810 

410 

510 

630 

770 

910 

1070 

1240 

1430 

1630 

22 

220 

300 

890 

490 

610 

730 

870 

1020 

1190 

isec 

1550 

23 

210 

280 

870 

470 

580 

700 

830 

98011140 

1300 

1480 

24 

200 

270 

360 

450 

560 

670 

800 

940 

1090 

1250 

1420 

25 

190 

260 

340 

430 

530 

650 

770 

900 

1050 

1200 

1370 

26 

180 

250 

830 

420 

510 

620 

740 

870 

1010 

1150 

1310 

27 

180 

240 

820 

400 

500 

600 

710 

830 

970 

lliC 

1260 

28 

170 

230 

800 

890 

480- 

580 

690 

800 

930 

1070 

1220 

29 

170 

230 

290 

870 

460 

560 

660 

780 

900 

1030 

1180 

WEIGHT  OF 
/ 

A  CUBIC  FOOT  OF  SUBSTANCE. 

Iverag* 

NAMES  OF  SUBSTANCES.  V«*ht 

•    Lit 

Anthracite}' solid,  of  Pennsylvania,                            •  •       93 

'•'          broken,  loose,                    -       »         *  •            64 

"              • "        moderately  shaken,            •         .  •       68 

"          heaped  bushel,  loose,         -         «       „*  •          (80) 

Ash,  American  white,  dry,      ?     .    »/      »         •        •  -       38 

Asphaltum,        -         -         •    f;  *.<•••        •  •            87 

Brass,  (Copper  and  Zinc,)  castj      •»        »       .»         •  -     604 

"      rolled,     -        -         .       ,*        *        *•       *  "         624 

Brick,  best  pressed,'                 •         »•       •        «         •»  •     16O 

"      common  hard,          -         -         ...         *  -          126 

"      soft,  inferior,          -         -         •         «         •         -  -     100 

Brickwork,  pressed  brick,            -   •.     -         -         -  140 

"           ordinary,       -         -  -112 

Cement,  hydraulic,  ground,  loose,  American,  Rosendale,         56 

",  «'  "          "  H          Louisville,          6O 

"             "               "          "      English,  Portland,  -           90 

Qherry,  dry,           -         -         -         -         -      ' .-         •  •       42 

Chestnut,  dry,    -        -        -        -        •        -  -           41 

Coal,  bituminous,  solid,           -         -         -         -         •  -84 

«'             "            broken,  loose,          -         -         -  .    49 

««             "            heaped  bushel,  loose,            •         -  •      (74) 

Coke,  loose,  of  good  coal,  27 

"         "       heaped  bushel, .-      (3£>l 

Copper,  cast,      -    ^    -                           -      .  -  642 

rolled,  648 

Earth,  common  loam,  dry,  loose,         -    '     -         -  -            78 

"                        "       "    moderately  rammed,  95 

"       as  a  soft  flowing  mud,               •        «•  108 

^bony,  dry,.          ..,.».  70 

EJm,  dry,           .,_..».  36 

Flint,     ^                         -         •                  «        «  102 

Class,  common  window,                                  •         »  £         167 


347 
WEIGHT  OF  SUBSTANCE. 

(CONTINUED.) 

Average 

NAMES  OF  SUBSTANCES.              .  w««ht 

Ite 

Gneiss,  common.             .......  [QQ 

Gold,  cast,  pure,  or  24  carat.                  -          ...          .  1204 

"      pure,  hammered,            -         -          .          .         .         .  1217 

Granite,             --.....„  ^70 

Grave!,  about  the  same  as  sand,  winch  see 

Hemlock,  dry,       .                   -          .....  25 

Hickory,  dry,    - 53 

Hornblende,  black,        -.-..,.  203 

Ice,                                               -         .         .        -        .  58.7 

Iron,  cast.      .........  450 

wrought,  purest,         .-..-„  485 

average, 480 

Ivory, 114 

Lead, 711 

Lignum  Vitx,  dry, 83 

Lime,  quick,  ground,  loose,  or  in  small  lumps,          -         «•  53 

thoroughly  shaken,   -  75 

"          "           "            "      per  struck  bushel,          -         -  (881 

Limestones  and  Marbles,  ......  188 

"                        "         loose,  in  irregular  fragments,       -  96 

Mahogany,  Spanish,  dry,             -         -         -         -         -  "  53 

Honduras,  dry,     -          .....  35 

Maple,  dry,       .-.-..-.  49 
Marbles,  see  Limestones. 

Masonry,  of  granite  or  limestone,  well  dressed,             -  185 

"    mortar  rubble,    -         -                   *••/:-         -  154 

"    dry             ••       (well  scabbled,)         -         -  138 

••    sandstone,  well  dressed,       -         -         -         -  144 

Mercury,  at  32°  Fahrenheit, 849 

Mica, 183 

Mortar,  hardened, 103 

Mud,  dry,  close.  -;  .         .         .          •  80  to   110 

wet,  fluid,  maximum;         -         -  120 

Oak,  live,  dry,       .........  £9 


"WEIGHT  OF  SUBSTANCES. 

(CONTINUED.) 

NAMES  OF  SUBSTANCES.  Weight 

Oak,  white,  dry,        ...«**.          62 

"    other  kinds,  -        -        -        *       *        •   32  to  45 

Petroleum,        -.-•.*.-          ^55 

Pine,  white,  dry,  -        •        »        •        »       *        -      25 

"    yellow,  Northern,     -        -        -        «       »        ?  34 

"         "       Southern,          -        -        •        *        *        -       45 

Plarinum,          -        -         -        -        -        »        9        -       1342 

Quartz,  common,  pure,  -        .        .        .        »        .     165 

Rosin,     -        -        -    £"-        -        »        «        +        *  69 

Salt,  coarse,  Syracuse,  N.  Y.  -       .»        -        *        -       45 

"     Liverpool,  fine,  for  table  use,\  .-»        *        •        *.  49 

Sand,  of  pure  quartz,  dry,  loose,     -        -         -  9Q  to  106 

"     well  shaken,  -        .        -        ,       .«       99  to  117 

"     perfectly  wet,       -         -        -        *        -         120  to  140 

Sandstones,  fit  for  building,  *        •  151 

Shaies,  red  /or  black,      -  -        -        -        -        .     162 

Silver,      -        -        -        -        -        -        -        „•-         655 

Slate,  -        -         -        -..^-        .  •     .        .     175 

Snow,  freshly  fallen,          -        -        -        -  5  to  12 

"       moistened  and  compacted  by  rain,        -        .-    15  to  5O 
Spruce,  dry,      -•        -        -        .        -'+*'-  25 

Steel.  -        -        -        »-„.»,*        .    490 
Sulphur,  -..        -       •-        ».*        -         125 

Sycamore,  dry,  ;-•      -        -        -        -        »-      •        -X87 

Tar,          -         -       .  -        -  -      -        -         .        .        .  62 

Tin,  cast,     -n-        -        -        -        -        *',*-.    459 

Turf  or  Peai,  dry,  unpressed,  -  -  «...  20  to  30 
Walnut,  black,  dry,  ,  .  -  .  -.-'-.,-  38>' 
Water,  pure  rain  or  distilled,  at  60°  Fahrenheit,  ,  62# 

"       sea,  -         -         -.-        .-.        -64 

Wax,  bees,  .  -  ,  .  .  -  -  -  6O.5 
Zinc  or  Spelter, v  ........  437 

Green  timbers  usually  weigh  from  one-fifth  to  one-half  more 
than  dry. 


349 

ROUND  CAST  IRON  COLUMNS. — Safe  Load  in  Tons  of 
2, ooo pounds;  safety,  6. — These  tables  are  based  on 
columns  made  of  the  best  iron,  perfectly  molded  and 
with  both  ends  turned. 


M 

Ovtlide  Diameter.  8  in. 

4 

m 

Ontsl.le  Diameter,  4  IB". 

'3 

36  in. 

X  »n. 

1  in. 

• 
•i 

*/2  in'- 

H  in. 

lin. 

3 

44,070 

69,890 

71,190 

4 

61,020 

85,880 

106,220 

4 

*9,8frl 

53,535 

63,686 

6 

56,1  40 

79.202 

98,02(1 

i 

84,579 

46,992 

55,859 

6 

51,246 

72,124 

KD.81I6 

6 

30,23  I 

4  1  ,083 

48.835 

7 

46,652 

65,968 

82,035 

7 

26,268 

35,698 

42.433 

s 

41,868 

58,912 

72,865 

8 

22,812 

81,001 

36,851 

9 

37,912 

53,303 

65,926 

9 

19,844 

26,967 

32,056 

10 

33,885 

47,690 

58,985 

10 

17,889 

28,564 

28,010 

11 

80,701 

42,681 

53.01  1 

It 

1.6,147 

20,694 

24,630 

12 

27,476 

38.671 

47,880 

1* 

1  3,402 

18,213 

21,650 

13 

2  0.0410 

34,794 

43,167 

13 

11,786 

16,123 

19,228 

14 

22.464 

31,616 

39,104 

14 

10,469 

14,335 

17,097 

15 

20,5  1  1 

28,667 

36,504 

15 

9,463 

'12,847 

15,271 

16 

18,557 

26,1  18 

32,304 

Ootiide  Diameter,  6  in. 

Outside  Diameter,  <5  in. 

&in. 

fc  in. 

lin. 

fcin. 

lin. 

IK  i". 

6 

79,104) 

141,250 

118,000 

6 

140,120 

177,410 

210,180 

6 

74,118 

13  2  ,3  5  3 

105,838 

7 

132,782 

168,1*20 

199,174 

7 

68,996 

123,207 

98,566 

8 

125,253 

168,587 

187,880 

8 

63,886 

114,082 

91,266 

9 

117,676 

148,993 

176,514 

9 

68,951 

105,270 

84,216 

10 

109,945 

139,205 

164,908 

10 

64,261 

96,895 

77,516 

11 

108,021 

130.438 

1A4,;>»2 

11 

49,876 

89,062 

71,250 

1  2 

96,119 

121,7011 

144,179 

12 

45,826 

81,832 

65,466 

13 

89,6I2i  113,448  134.403 

in 

42,105 

75,187 

60,150 

14 

83,514  105,739  125.371 

14 

S8,710 

69.125 

55.300 

15 

77,810;   98,517 

1  1  6,7  1  5 

15 

85,618 

63,603 

60,833 

16 

72,532i   91,835 

108,798 

16 

32,830 

58,625 

46,900 

1  7 

67,633   8  ;),<;  3  2 

101,449 

17 

30,298 

54,103 

43,283 

18 

63.094   79,886 

94.64'.' 

.18 

28,003.'   50.006 

40,005 

19 

58,9621   74.653!'  8S.44:! 

19 

25,931!   16,306 

37,045 

20 

55.13I!   69,S03 

82,697 

20' 

24,056 

42,957 

34.366 

21 

5l,5S4j   65,818 

7  7,:J7»> 

22 

48,348 

•;  i  ,2  1  5 

72,523 

1 

23 

45,365 

»7,4«H 

68.048 

0«Mi<U  Diameter,  7  i. 

Outfttde  Diameter,  8  iu. 

Kin. 

1  in. 

\14  in. 

fc  in. 

1  in. 

l!'i  ni. 

7 

166,110 

212,440 

255,880 

8 

193,230 

•2  4  S,  600 

•299,4  r.O 

M 

158,664 

202.917 

243,938 

9 

185,671 

•2:{8.H;<;  287.7:$; 

9 

151,086 

193,226 

232,282 

10 

177,942 

•_'2S.93%J:  27."»,7.">9 

10 

148.288 

183,375 

220,440 

11 

170.110 

2  IS.  85  61  263.628 

11 

135,769 

173,636 

208,783 

12 

162,279 

L'OS,;sO  251,48.* 

12 

128,198 

163.954 

197,094 

18 

154.359 

P.»S.688  23S»",26H 

IS 

120,936 

154,667 

185.930 

14 

146,700 

I8S.7SSI  2t»7,34:{ 

14 

119,948 

145,730 

175,186 

1  5 

l:{»,6r»:> 

1  79,674'  216.42:* 

15 

107,824 

137,258 

165,002 

16 

ue.5ri'j 

170,535:  205.417 

10 

101,062 

129.250 

1  55,  3  7:, 

17 

1  •.',•>,;  S  I   16  1.832  194.93I 

17 

95,123 

121.654 

146,244 

IS  |  119.328  15:5.516  1X4.917 

18 

89,567 

114,548 

137,701 

19  n:i.i5o  145,574  i7;>,3.-><» 

Itt 

84,275 

107,780 

12  9.  5  65 

20  '  I07.3O2 

I3S.050!  166,487 

30 

79,380 

101.520 

122.040 

21  !  101.796 

130.966 

i:,7,7.,4 

21 

74,798 

9&,660j  11  4,  995 

22    96,580 

124.256 

149.672 

22 
23 

70,589 
664686 

90,277  108,525 
85,i20!  I08,4."»S 

28 
24 

9  1.6.'.  li 
'S7.O01I 

1  17,920 
1  1  1.942 

1  1-2.040 

i:s  4.  *::•.• 

554 

62.980 

8<M83   U6.750 

8  a 

82.695 

I06.X92  liS.l.il 

R£)UND  CAST  IRON  COLUMNS— (Continued). 


- 

OdUlde  DiEtoeler,  )  5  In. 

J3 
tf. 

e 

•1 

Outside  Diameter,  16  In. 

lin 

1&  in. 

vita.. 

lj£to, 

2  in. 

2%  in. 

16 

496,974 

718,798 

922.884 

16 

772,129 

993.6481,198.139 

16 
17 

486,723 
496,261 

708,972    903.058 
688,838|  884.518 

17 

18 

767.  US 
741,095 

974.  785J1,  175,918 
955.158!l,161,830 

18 

460,664 

673,5661  804.910 

19 

726,521 

986,397jl.  127.523 

19 
20 
21 

464,978 
444,242 
483,467 

658,045    844,980 
642,525i   825,050 
626,940    805.038 

20 
21 

2  2 

711,0421     916,3I2il,103,34ft 
695.3911     895.149[l.079,067 
879.610!     871.  750:i.054,674 

22 

422,78f 

611,419 

785.108 

28 

604.031!     854.  7»6J1,  080,400 

23 

412,903 

595,898 

76i,178 

2  I 

048.452     88  4.7401  1.006,22  5 

24 

401,405 

580.568 

745.45)3 

25 

632.9  U 

814.773 

982,156 

25 

890,938 

565,425) 

726,054 

26 

617,567 

794,962 

95  8.  '29!* 

26 

880,651 

550.417 

706,777 

27 

802,329'     775,367 

984,057 

27 

870,401 

635,733 

687,900 

28 

587,806;     756,016 

011.828 

2H 

860.241 

621,220 

669,28(5 

29 

572.537      737.017 

888.365 

29 

850,565 

607,035 

651.071 

80 

o57,988 

718,281 

865,841 

30 

840,933 

403.105 

633.1  S3 

31 

543.702     699.918 

843,681 

81 

880.921 

470.49-2 

615,704 

8-2 

529.69*!     681.866 

822,845 

82 

822,329 

466.198 

595,633 

33 

515,060 

664,180 

800,633 

Outside  Diameter,  17  In. 

On  JeUe  Diameter,  17  In. 

IHin. 

2  in.*     1    2y2in.. 

1)6  in. 

2  in. 

Wz  in. 

17 

825,852 

,065.025,  1/280,84  4 

26 

(J80.50;; 

885.856 

1,070,353 

1'8 

S09,752 

,045,798'l.2G8.<H2 

27 

671,01b 

865,875 

1.046,216 

19 

795,883 

,026.  19$!U24  0.089 

28 

655,758 

846.176 

1.023,415 

20 

779,994 

.000,495  1.  216.125 

20 

640,031 

825.6G7 

998,841 

21 

764,510 

986.515  1.101.982 

30 

625.661 

807,846 

975,496 

22 

748,952 

906.  43!)  1.167.726 

81 

(510.007 

788,807 

952,492 

23 

788,832 

946.270  1.1  43,  355 

32 

&  96.4  Go 

769,645 

929.944 

24 

317.618 

22a.oo<;    im,87i 

33 

582.132 

744,267 

903,737 

25 

702,060 

905,  981i  1.09  4.  01  5 

34 

560.206 

730.626 

888.7W8 

NEW  STEEL   RAILS  USED  AS   LINTELS  OR  GIRDERS. 
Safe  load  In  tons  or  2000  )bs. 


A 

Length 

f 
I 

2 

1    8 

_L 

5.50 
5  05 

5 

3.50 
4.00 

7           8 

i) 
2:50! 

2.70  , 

i 

62  Ib.  rail, 
60  Jb.  rail, 

per 
ycr 

yardjlO.76 
yard  12. 

7.00 
8.00 
•n  n\n 

47u 

3.   J   2.76 

«.r>o;  a. 

TWiHrwil  i 

in  i 

.          !n 

i  >  t  \ 

n  (i?  .\  (i  IIOA 

n  i  •>.  •.  n  i  9Ain  09  R. 

A  OrtA    ' 

0 .170jO.226jO.SOO  i 


tin  H  1 15 

«<>|    I.50J    1.40; 
1  SOJ    1 .70     1  00"J 


-  j 


AREAS    OF   CIRCLES, 

Advancing  by  Eighths. 


'      .0 

n 

'« 

rf* 

>ij 

.9* 

•  K 

•« 

i. 

.0 

.0122 

.0490 

.1104 

.  1963 

.3068 

.441! 

.6019 

.7854 

.9940 

1.227 

1.484 

1.767 

2.073 

2.405 

2.701 

3/14  1C 

3.546 

3.976 

4.430 

4.908 

5.411 

5.939 

6.4»1 

?.0€8 

7.669 

8.295 

8.946 

9.621 

10.32 

11.04 

11.79 

12.56 

13.36 

14.  18 

15.03 

ir,.90 

16.80 

17.72 

13.06 

19  63 

20.62 

21.64' 

22.69 

23,.  7  5 

24.85 

25.96 

27.10 

28.27 

29.46 

30.67 

31.91 

33.18 

34.47 

85.78 

37.12 

38.48 

39.87 

41.28 

42.  7i 

44.17 

45.66 

47.17 

48  70- 

50.26 

51.84 

53.45 

55  .  08 

5G.74 

58-42 

60.  J3 

6  1  .  86 

€3.61 
78.54 

65.  39 

80.51 

67.  20 
82.51 

69  .  0- 

84.54 

86.59 

88.66 

90.76 

92.  8S 

95.03 

97.20 

99.40 

101   6 

103.8 

106.1 

108.4 

110.7 

113,0 

115.4 

117.8 

120.2 

122.7 

125.1 

127.6 

130.1 

132.7 

135.2 

137.8 

140.5 

143.1 

145.8 

148.4 

151.2 

153.9 

15G.6 

159.4 

162.2 

165    1 

lf.7.9 

170.8 

173.7 

17«.7 

179.6 

182.6 

185.6 

168.6 

191.7 

194.8 

197.  a 

201.0 

204.2 

207.3 

210  5 

213.8 

217.0 

220.3 

223.6 

226.9 

230  3 

23J.7 

237.1 

240.5 

243.9 

247.4 

250.9 

254.4 

258.0 

261.5 

265.1 

268.  8 

272  .'4 

276.1 

279.8 

283.5 

287.2 

29  i  .  0 

294.8 

298  .  6 

302.4 

306.3 

310.2 

314.1 

318.  1 

322.0 

326  .  0 

330  0 

334.1 

338.1 

342.2 

<  ]    C 

t 

346  3 

350  4 

354.6 

358   8 

363  .  0 

367.2 

371.5 

375  8 

380.1 

884   4 

388.8 

393.2 

397  6 

402  .  0 

406.4 

410.  9 

452.3 

457   1 

461  .8 

466  6 

471.4 

476.2 

481.  I 

485.9 

530.9 

536.0 

541.1 

5(52.0 

567.2 

572.5 
615.7 

577.8 
62  1.2 

583.2 
626  .  7 

632.3 

637  9 

64  3.  5 

649.1 

654.8 

660.5 

666.2 

671.9 

677.7 

683  .  4 

689.2 

695.1 

700.9 

706.8 

712.7 

718.6 

724.6 

730.6 

736.6 

742-6 

748.6 

754.8 

760.9 

767-0 

773.1 

779.3 

785.5 

791.7 

798.0 

804.3 

810.6 

816.9 

823.2 

829.6 

836.0 

842.4 

818.8 

855.3 

861.8 

368.3 

874.9 

881.4 

888.0 

894.6 

901.3 

907.9 

914.7 

921.3 

928  .  1 

934.8 

941.6 

948.4 

955  .  3 

9(52.  1 

969.0 

975.9 

982.8 

989  8 

996.8 

1003.8 

'.010.8 

1017.9 

1025.0 

1032.1 

1039.2 

046.8 

053.5 

1  Ot>0.7 

1068.0 

1075.2 

1082.5 

1089.8 

1097.  1 

104.5 

111.8 

Iii9.  2* 

1126.7 

1134.1 

1141.6 

1149.1 

1156.6 

164.2 

171.7 

1179.3 

1186.9 

1194.6 

1202.3 

1210.0 

1217.7 

225.4 

233.2 

1241.0 

1248.8 

1256.  ff» 

1264.5 

1272.4 

1280.3 

288.2 

296.2 

1304.2 

1312.3 

320.  & 

1328.8 

1336.4 

1344.5 

352.7 

360.8 

1369.0 

1377.2 

385.4 

1393.7 

1402.0 

1410.3 

418.6 

427.0 

1435.4 

1443.8 

452.2 

1460.7 

1469.1 

1477.6 

486.2 

494.7 

1503.3 

1511.9 

520.5 

1529.2 

1537.9 

546.6 

,r>55.3 

564  .  0 

1372.8 

581.6 

590.4 

1  599  .  3 

1608.2 

617.0 

626.0 

634  .  9 

1643.9 

1652.9 

352 
CIRCUMFERENCES  OF  CIRCLES. 

Advancing  by  Eighths 

CIRCUMFERENCES. 


'  .0 

.* 

., 

t« 

-H 

.* 

.H 

•H 

.0 

-892-7 

.7894 

1.178 

1.570 

1.963 

2.356 

2.748 

8.141 

8.5S4 

8.927 

4.319 

4.712 

5.  105 

5.497 

5.890 

6.288 

6.675 

7.0«8 

7.461 

7.854 

8.246 

8.639 

9.032 

9.424 

9.817 

10.21 

10.60 

10.99 

11.38 

11.78 

12.17 

12.  56 

12.95 

13.85 

18.  M 

14.13 

14.52 

14.92 

1J5.31 

15.70 

16.10 

16.49 

16.  8ft 

17.27 

17.67 

18.06 

is.  ir> 

18.84 

19.24 

19.68 

20.02 

20.42 

?O.Rl 

21.20 

2  J  .  5» 

21.99 

22.38 

22.77 

23.16 

23  56 

23.95 

24  .  34 

21   71 

25.18 

25.52 

25.9 

26.31 

^t,  .  70 

27.0-.I 

J7.48 

27.  NH 

28.27 

28.66 

29.05 

29.45 

SS.  84 

SO.  2  3 

,-Mf.sa 

31.02 

81.41 

81.80 

32.20 

32.59 

32..  18 

33.37  '* 

.3:3.77 

34.  IK 

84.55 

84.95 

85.34 

85.<?3 

86.1? 

36.52 

SO.  91 

37.3ft 

37.69 

88.09 

38.48 

88.87 

39.27 

39.66 

40.05 

40.44 

40.84 

41.28 

41.62 

42.01 

42.41 

42.80 

43.19 

43.98 

44.37 

44.76 

45.16 

45.55 

45.94 

46.33 

46^73 

47.12 

47.51 

47.90 

48.30 

48.69 

49.08 

49.48 

49.87. 

50.26 

50.65 

51.05 

51.44 

51.83 

52.22 

52.62 

53.01 

53.40 

58.79 

54.19 

54  .  58 

54.97 

55.37 

55.76 

5f%.  15 

56.54 

56.94 

57.33 

57.72 

58  -  1  1 

58.51 

58.90 

59.29 

59.69 

60.08 

60.47 

60.86 

61.26 

6  1  .  65 

62.04 

62  .*3 

62.83 

63.22 

63.61 

64.01 

64.40 

64  79_ 

65.18 

65.58 

65.97 

66.86 

66'.  75 

67.15 

67.54 

67.93 

68.82 

68.72 

69.11 

69.50 

69.90 

70.29 

70.68 

71.07 

71.47 

71.86 

72.25 

72.64 

73.04 

73.43 

73.82 

74.22 

74-61 

75.00 

75.39 

75.79 

76.18 

76.57 

76-96 

77.86 

77.75 

78.14 

78.54 

78.93 

79.32 

79.71 

80.10 

80.50 

80.89 

81.28 

81.68 

82.07 

82.46 

82.85 

83.25 

83.64   ' 

84.03 

84.43 

84.82 

85.21 

85.60 

86.00 

86.39 

86.78 

87.17 

87.57 

87.98 

88.35 

88  .  75 

89.14 

89.53 

89.92 

90.32 

90.71 

91.10 

91.49 

81.89 

92.28 

92.67 

93.06 

93.46 

93.85 

94.24 

94.64 

95.03 

95.42 

95.81 

96.21 

96.60 

96.99. 

97.89 

97.78 

98.17 

98.57 

98.96 

99.35 

99.75 

100.14 

100.53 

100.92 

101.32 

101.71 

102.10 

102.49 

102.89 

103.29 

103.  67 

104.07 

104.46 

I  04  .  85 

105.24 

105.64 

106.03 

106.42 

106.81 

107.21 

107.60 

107.99 

108.39 

108.78 

109.  17 

109.56 

109.96 

110.35 

110.74 

111.18 

111.53 

111.92 

112.31 

112.7% 

118.10 

118.49 

113.88 

114.28 

114.67 

115.06 

115  45 

115.85 

116.24 

116.68 

117.02 

117.42 

117.81 

118.20 

118.61 

118.99 

119.38 

119.77 

120.17 

120.56 

120.95 

121.34 

121.74 

122.13 

122.52 

122.92 

128.31 

123.70 

124.09 

124   49 

124.88 

125.27 

125.66^ 

126.06 

116.45 

126.84 

127.24 

127.63 

128-02 

128.41 

128.81 

129.20 

127.5 

129.98 

180.88 

130.77 

IS  i.  ift 

1.55 

181.95 

132.34 

132.7 

133.  13 

133.52 

133.91 

134.30 

i3i  .  70 

135.09. 

135.48 

135.8 

136.27 

136.66 

137.05 

137.45 

137.84' 

138.29 

138.62 

139.0 

139.41 

139.80 

140    19 

140.59 

140.98 

Ml.  37 

141.76 

142.1 

142.55 

142.94 

143.34 

143.73 

144.12 

353 

Weight   of  Cast   Iron  Columns  Per  Lineal  Foot 
Foot  of  Plain  Shaft. 


:a 

THICKNESS  OF  METAL. 

I 

Kin. 

Xln.j^m. 

Mini 

* 

n 

lin 

lifcin. 

IK  in. 

iy2m. 

MK 

2  tii 

2 

4.3 
6  5 

6.0 
7  8 

7  4 
9  8 

8  4     9.2     9  7 
11  5    12  9    14  0 

ul:.:: 

3 

3H 

6.8 

8  0 

9  7 
11  5 

12  3 
14  7 

146 
17  6 

16.6 
20.3 

18  3 

22  6 

«?  ::::. 

4 

9.2 

13  3 

17  .2 

20.7 

23.9 

2f 

.8    29.5    .. 

10.4 

15  2 

19  6 

23.81 

27  e 

31   1    34  4!    37.3 

39'^ 

6 

11.7 

17.0!  22  1 

26.9! 

31  3 

3c 

4 

39  .1 

42  ? 

46  fl 

12.9 

18  9  24  5 

29.9' 

35  0 

& 

.7    44  2 

48,3 

52.:. 

6 

14.1 

20.7   27.8   33  0 

as  - 

44  0 

49  1 

53.9 

58.3 

6V$ 

15  3 

22  .6 

29  51  36  1 

42  3 

48  '6 

54  0 

69  4 

64.4 

'  r. 

16  6 

24  4   31  9 

39  1 

46  C 

52 

.6 

58  fl 

64  9 

70.6 

81  0 

17  8j  26  2;  34  4 

49  7 

Bf 

.9    63  f 

7U.4 

7fi  7 

88  4:.    - 

t'-'  ' 

8 

19  Ol  28  1   36  8 

45  3 

53  4 

61 

68  ', 

75  9     82  8i    95  7!     . 

20.2 

29  9!  39  3 

4*  3> 

57   1 

65  ft 

73  e 

HI  5 

89  0    HM.  1;  .-.  

0 

21  5 

31  8   41  7 

51  4 

60  8 

69  8 

78  S 

87  0 

w  i  110.5!.  ... 

9H 

22  7 

33  6,  44.2 

54  5j 

64  4 

74 

1 

K<  5 

92  5 

101  I 

117.8 

J:jy.2'  

10 

23  9 

35  4!  46  8 

5-  5 

OS   1 

7S  4 

88  4     08  0 

107  4    125.2 

HI  : 

ir.7  r 

11 

25.2   37  3   49  1 
26  4'  39.1    51  6 

60  6: 

63  7' 

71   R 

,-,, 

fe, 

87  0 

93  3!  103  f> 
98  Si  109  1 

119  7 

132  5 
139  9 

150  3,  1«A  «» 
158  9;  17«  T 

27  6   4J  0.  54  8 

66  7 

7y  2 

91 

3 

Iff*  1.  114  6 

125  8    147  3l 

167  &,  18C  .5 

I 

} 

12 

28  8  42  8'  56  5 

69  K 

82  6 

95 

*? 

108  0   120  1 

131  9!  15*:  6 

176  l!  196  3 



44  fl1  58  9 

72  9, 

865 

ww  9 

112  9 

126  6 

m  i 

162.0 

184  7 

20«5  2 

13 

46  5  61  4 

759 

90  2 

104 

2 

117  R    131.2 

U4  2    169  4    103  Ji  216  t> 

13/4 



63  8 
663 

79  0 

m  \>m  r, 

97  e!l!2  8 

!£.'  7 

136  7 
142  2 

151J  3   176  71  201  9j  2L'u  i1 
15*5.5!  1^4  l!  210  ,V  235  6 

44Vi 

'  68.7 

85  2.1 

01  2 

117 

0:1.12  .-,i    147   7 

102  6i   iyi  4 

219  I 

246  * 

15 

.    _  •'  ...     71  2 

88.2104  9 

121 

3 

137  A!   \rS,  '2 

168  7 

108  8 

*»7  6 

.255  5 

16 

7fi  1 

94  3il 

V  :5 

HJU7   3     1»U    .< 

!<"*!  (V  213  i)\  244  ^ 

274  \t 

i: 

81  0 
86  9 

100  5:119  71138 
106  6127  Oil47 

1 

157  1 
166.0 

175  ;} 

1S6  4 

1M8  3j  228  3  ml  0 
24Ja  6   243  0   279  2 

.294  5 
314   1 

u 

90  8 

112  8il34  4 

155 

7 

170  7!   197  4 

217  8 

257  7    296  4 

S«  8 

ft 

"."..i       ..    95  7 

118  9;  141  '. 

164 

.3  IWJ.5J.208  5 

230 

274  4    313  5 

Sfvl  4 

INCREASE  IN  WEJUE 

T  fOrt 

y-i  IN   I  NCR*  AS  E  IN  DIAMETER 

*•«. 

*». 

*m 

ft  in 

HM, 

» 

m. 

l,n     I 

Sg  in,  l 

,,,, 

1             I 
fcm.  Uiin     2  in. 

•7 

1  S 

2.5 

3  i 

37 

4 

T- 

77  \ 

6  1 

74 

86     [.».» 

354 

Weight  of  Square  or  Rectangular  Cast  Iron  Col* 
umn  Shafts  Per  Lineal  Foot. 

EXAMPLE  :  Column  6"  X  10"  X  i7  +  10'  o'.  6"  X 
jo"  =  1 6"  X  2  =  32.  Following  out  line  on  which  32  is 
found  in  left  hand  column  to  column  headed  i",  we  find 
the  weight  per  foot  to  be  87.5  pounds,  which,  multiplied 
by  10'  i"  =  875  pounds. 


jftul 

i  -?  24 

M  ETAL 

*•• 

V 

23.8 

28.7 
84.2 

1" 

w- 

IX" 

"»" 

HT 

2" 

14 
<16 

18.6 
22.5 
26.4 

21.1 

25.8 
30.5 

25.0 
31.3 
87.6 

26.4 
38.4 
40.4 

27.3 
35.1 
43.0 

28.1 
87.5 
46.9 

49.2 

60.0 

M 

80.8 

86.2 

89.7 

48.8 

47.4 

50.8 

56.3 

60.2 

•2.6 

20 

34.2 

39.8 

45.1 

60.0 

64.6 

68.6 

65.6 

71.1 

76.0 

22 
f4 

26 

88.1 
42.0 
45.9 

44.6 
49.2 
53.9 

50.6 
56.1 
61.5 

66.3 

62  6 

68.8 

61.5    66.4 
68.51   74.2 
7  ft.  6]  82.0 

75.0 
84.4 

93.8 

82.0 
93.0 
103.9 

87.6 
100.0 
112.5 

28 

49.8 

68.6 

67.0 

76.0 

82.6 

89.8 

103.7 

114.8 

125.O 

90 

53.7 

63.8 

72.6 

81.8 

89.6 

97.7 

112.5 

126.8 

192.6 

12 

57.6 

68.0 

77.9 

87.6 

96.7 

105.5 

121.9 

187.7 

150.0 

94 

61.5 

72.7 

83.4 

93.8 

108.7 

118.3 

131.3 

147.7 

162.5 

86 

65.4 

77.3 

88.9 

100.0 

110.7 

121.1 

140.C 

158.6 

175.O 

88 

69.8 

82.0 

94.8 

106.3 

117.8 

128.9 

150.0 

169.5 

187.5 

40 

73.2 

86.7 

99.8 

112.6 

124.8 

136.7 

159.4 

180.5 

200.0 

42 

77.1 

91.4 

105.3 

118.8 

131.8 

144.6 

168.8 

191.4 

212.6 

44 

81.0 

96.1 

110.8 

126.0 

138.8 

152.3 

178.1 

S02.3 

225.O 

46 

84.9 

100.8 

116.2 

131.3 

145.9 

160.2 

187.5 

213.8 

2S7.6 

48 
60 

88.8 
92.8 

105.5 
110.2 

121.7 
127.2 

137.6 
143.8 

152.9 
159.9 

168.0 
175.8 

196.9 
206.3 

224.2 
235.2 

250.0 
262.6 

62 

96.7 

114.8 

132.6 

150.0 

167.0 

183.6 

215.6 

246.3 

275.0 

64 

100.6 

119.5 

138.1 

156.3 

174.0141.4 

226.0 

257.0 

287.6 

66 

104.5 

124.2 

148.6 

162.6 

181.0199.2 

234.4 

268.0 

300.0 

68 

108.4 

128.9 

149.0 

168.8 

188.1  207.0 

243.8 

278.9 

312.5 

60 

112.3 

133.6 

154.5 

175.0196.1  214.9 

253.2 

289.8 

825.0 

62 

116.2 

138.3 

160.0 

181.3  202.1  222.7 

262.5 

800.8 

387.5 

64 

120.1 

143.0 

165.4 

187.5209.2230.6 

271.9 

811.7 

350.0 

68 

124.0 
127.9 

147.7 
162.3 

170.9 
176.4 

193.81216.2 
200.o!223.2 

238.3 
246.1 

281.3 
290.6 

822.7 
336.6 

362.6 
875.0 

70 

131.8 

157.0 

181.8120613  230.3  253.9 

300.0 

344.5 

S87.5 

;2 

135.7 

161.7 

187.7  212.5287.3261.7 

309.4 

865.5 

400.0 

74 

139.5 

166,4 

192.8  218.81244.3  269.5 

818.8 

366.4 

412.6 

76 

78 

143.5 
147.4 

171.1 

175.8 

198.3 
203.7 

226.0J261.8 
23I.3J268.4 

277.3 
285.2 

328.1 
337.6 

877.3 
383.3 

425.0 
487.5 

80 

151.3 

1  &0.5 

20».2 

237.6265.4'293.0 

340.9     399.2 

450.0 

355 
CUBIC  MEASURE. 


1.     £      0005788 
1*728.          1. 
46656-        27. 


Tard. 

.000002144 
.03704 


J. 


Oubir  Metre* 

.000016386 

.028315 

764513 


A  CUBIC  FOOT  IS  EQUAL  TO 


1728  cubic  inches 
.037037  cubic  yard 
803564  U   S    struck  bushe) 
of  2150  42  cub  in 
U  S  pecks 
U.  S   liquid   gallons 
of  231  cub   in. 

$.42851    U.  S   dry  gallons  of 
268  8025  cub  in 


321426 
7.48052 


29  92208  U.  S  liquid  quarts. 
25.71405  U  S  dry  quarts 
59  84416  U  S  liquid  pints 
51  42809  U  8.  dry  pints. 
239.37662  U.  S.  gills 

.26667  flour  barrel  of   3 

struck  bushels 
23748  U  8.  liquid  barrel 

of  31  >£  gallons 
\ 


A  cubic  inch  of  water  at  62?  Fahr  weighs  252  458  grains. 
A  cubic  foot  of  water  ai  02  Fahr  weighs  1002. 7  ounces. 
A  cubic  yard  of  water  at  62'  Fahr.  weighs  1692  pounds 


FRECNH  CUBIC  OR  SOLID   MEASURE. 


Pint 

Quart. 

Buah. 

Cubic  Inch. 

Cu  Ft 

Centilitre  • 
Decilitre  .  • 
Litre  j 

Dry  .  . 
Liquid 
Dry     . 
Liquid 
Dry  .. 
Liquid 
Dry  .. 
Liquid 
Dry    . 
Liquid 
Dry 
Liquid 
Dry 
Liquid 

.0181 

.0211 
.1816 
.2113 
1.816 
2.113 

2i  13 

211  3 

• 

J     61016 

6.1016 
61.016 
610.16 

6101  6 
(51016. 

.0353 
.3531 
3.531 
35.31 
353.1 

0908 

1056 
908 
1.056 
908 
1056 
90.8 
1056 

10565 
10565. 

2837 

Decalitre  • 

Hectolitre  .  • 

Kilolitre  OT  A 
Cubic  Metre  / 

MyrioWtre 

2.837 

28.37 
283.7 

AVOIRDUPOIS   WEIGHT. 

The  standard  avoirdupois  pound  is  the  weight  of  27.7015 
cubic  inches  of  distilled  water,  weighed  in  the  air,  at  39.83 
degrees  Fahr.,  barometer  at  thirty  inches. 


Ounces. 

Pounds. 

Quarters. 

Cwt8. 

Ton. 

1. 

=        .0625  == 

.00223  = 

.000558  = 

.000028 

16. 

1. 

.0357 

.00893 

.000447 

448. 

28. 

I. 

.25 

.0125 

1792. 

112. 

4. 

1. 

.05 

35840. 


2240. 


80. 


20. 


A  drachm  —  27.343  grains. 

A  stone       —  14  pounds. 

A  quintal    ~  100  kilogrammes. 


7000  grains    =     1  avoir,  pound   = 
5760  grains    =    1  feroy     pound  — 

Kilos  p.  sq.  ceiitim.    x    14.22       = 
Pounds  p.  sq.  inch     x       .0703  — 

1.21528  troy      pounds, 
.82285  avoir,  pound. 

Pounds  p.  sq.  inch. 
Kilos  p.  sq.  centiui. 

FRENCH  WEIGHTS. 

EQUIVALENT  TO   AVOIRDUPOIS. 


Gnic* 

<>,„,,. 

Pounds, 

Milligramme  
Centigramme  

Decigramme 

.0154& 

1543SI 

1.54031 

*  J352 
003527 

.000023 
.0002^ 

G  ram  ine 

15.4831 

.035275 

.00220* 

Decagramme.  .  .  . 
Hectogramme  
Kilogramme  . 
M  vrio*rvammc 

154.883 

1543.31 
15433.1 

352758 
3.52758 
35.2758 
352.758 

.022047 
220473 
2.20473 
22.0473 

Quintal 

3527  58 

220.473 

Millicr  or  T«Mmt» 

35275.8 

2204  73 

357 
SQUARE    MEASURE. 

Inches  Feet-  VnnJ  Perches.  Acre. 

1.       =       .00694  =   000772  --  .0000255  =  .0000001 5& 
144.  1.  .111  .00367  .000023 

1296.  9.  1-  .0331  .0002066 

39204.         272*.          30*.  1.  .00625 

6272640.       43560.        4840-  160  1 

100  square  feet       =  1  square. 
10  square  chains  -  I  acre. 
1  chain  wide       =•  8  acres  per  mile. 
I  hectare  =  2471143  acres. 

S=  27.878.400  square  feet. 
=    3.097.600  square  yards." 
=  640  acres. 

Acres  x     0015625     =  square  milei 

Square  yard  x     000000323=  square  miles 
Acres  x  4840=  square  yards 

Square  yards  x     0002066     =  acres. 

A  section  of  land  is  1  mile  square,  and  contains  640  acres. 

A  square      acre  is  208  71     ft   at  each  side;  or,  ;  20  x  198  ft. 

A  square  *  acre  is  147  58    ft  at  each  side.  or.  110  x  198  ft. 

A  square  *  acre  is  104  355  ft.  at  each  side,  or.    55  x  198  ft. 

A  circular     acre  is  235  504  ft   in  diameter 

A  circular  4-  acre  is  166  527  ft.  in  diameter 

A  circular  ±  acre  is  117.752  ft  m  diameter 


FRENCH    SQUARE    MEASURE. 


Square 

Q 

Q 

Millimetre. 

00154 

0000107 

000001 

Centimetre 

15498 

0010763 

.000119 

Decimetre 

15  498 

107630*5 

011956 

Met  or  Ccn 

1549  8 

10  76305 

1   19589 

Decametre 

154988 

1076  305 

119.589 

Hectare  .. 



107630  58 

1195H  95 

Kilometre  . 

'.38607  amis 

10763058 

1195895. 

Mynamei. 

38.607 

•  ..,'..  - 

35* 


SURVEYING  MEASURE. 


(LINEAL.) 


Inch**. 

Feet. 

Yard*. 

Chains. 

1. 

=   .0888 

=  .0278 

=  .00126 

12. 

1. 

.333 

.01515 

36. 

3. 

1. 

.04545 

792. 

66. 

22. 

1. 

63360.       5280. 


1760. 


80. 


Mile. 

.000015$ 
.000189 
.000568 
.0125 
1. 


One  knot  or  geographical  mile  =  6086.07  feet  -  1855.11 
metres  =1.1526  statute  mile. 

One  admiralty  knot  =  1.1515  statute  miles  =  6080  feet 


LONG   MEASURE. 

Inehe*.  Feet.          Yard*.          Poles.  Furl.  Mlie. 

1.  =  .083  =  .02778  =  .005  =  .000126  =  .0000158 
12.    1.      .333     .0606   .00151    .0001894 
36.    3.     1.       .182   .00454    .000563 
198.   16f    5*.       1.      .025      .003125 


7920.   660. 


220. 


63360.  5280.   1760. 

A  palm  =  3  inches. 
A  span  =  9  inches. 


40. 
320, 


1. 

8. 


.125 
1. 


A  hand  —  4  inches. 

A  cable's  length  —  120  fathoms. 


FRENCH    LONG    MEASURE. 


luches. 

Feet. 

Yards. 

MIk-8. 

Millimetre 

03937 

0033 

Centimetre 

!393G8 

.0328 

Decimetre 

3  9368 

.3280 

.10036 

Metre 

39.368 

3.2807 

1  09357 

Decametre  
Hectometre 

303.68 

32.807 

328  07 

10  9357 

100  357 

Oo2l;>4 

Kilometre 

3280  7 

1093  57 

t>2mo 

Myriametre  



32807. 

!00:V,  7 

;  -.H.vtn6 

359 
STRENGTH  OF  MATERIALS, 


ULTIMATE    RESISTANCE    TO    TENSION 
W  LBS.  PER  SQUARE  INCH. 

METALS. 

Atertf*. 

Brass,  cast, 18000 

"      *>re,          .......         49000 

Bronze  or  ^un  metal, 36000 

Copper,  cast.         -  -         .  19000 

sheet,  30000 

bolts,      .  .  36000 

w>re,  -         -    ^  -  60000 

Iron.  casi.  13400  to  29000,    -  ...         16500 

"       wrought,   round   or   square   bars   of    1    to  2   inch 

diameter,  double  refined,  -          6OOOO  to  54OOO 

••       wrought,  specimens  j£  inch  square,  rut  from  large 

bars  of  double  refined  iron,        .         60000  to  53OOO 
"       wrought,  double  refined,  m  large  bars  of  about 

7  square  inches  section,      -         -          46OOO  to  470OO 

wrought,  plates,  angles  and  other  shapes,  48OOO  to  61OOO 

plates  over  36' '  wide.       -          46000  to  6OOOO 

Wrought  iron,  suitable  for  the  tension  members  of  bridges, 
should  be  double*  refined,  and  show  a  permanent  elongation  of 
20  per  cmr  .n  ft",  when  broker*  m  small  specimens,  and  a  re- 
duction o»  -irea  of  26  per  cent  at  point  of  fracture 

The  modulus  of  elasticii)  of  Union  Iron  Mills'  double  refined 
bar  .ron  »s  25000000  tu  2,6000000,  from  tests  mado  on  firushed 
eyebars 

iron,  wire. 70000  to    10000O 

1     wire-ropes.  -        •        *>  -         9000O 

Lead,  sheet,     ....-.-.       3300 
Steel,  ......      65000  to  12000O 

Tin,  cast,          -  460O 

Zjnc,  -        -   '     -        -        -        -   *    -     700O  to  8000 


STRENGTH  OF  MATERIALS. 

(CONTINUED.) 

TIMBER,  SEASONED,  AMD  OTHER  ORGANIC  FIBE& 


Ash,  English,  »        „        ...-.-        .        .     17QOO 

«      American,    -        -        .        -        -         11000  to  14000 

Beech,      "  -  1500O  to  1800O 

Box,   -        -        -       w        *  •     \        ~        -        -         20000 

Cedar  of  Lebanon,  -        -.       *        -        -  -     11400 

"      American,  red,    -         •        *         -        -    /  -          1O3OO 

Fir  or  Spruce,  -  1000O  to  1380O 

Hempen  Ropes,  -        -        -        -        -         12000  to  16000 

Hickory,  American,  -         -         -        -    12800  to  18000 

Mahogany,  8000  to  218OO 

Oak,  American,  white,     -          -        -        -      «-         -     18OOO 

"     European,    -        -,      -        -        -         10000  to  19800 

Hne,  American,  white,  red  and  pitch,  Memel,  Riga,    -     10000 

long  leaf  yellow,  -         120OO  to  19200 

Poplar,     -        -        -  '     .        .        ,         ~        .        .       7000 

Silk  fiber,     ..---,..         52000 

Walnut,  black,  .,.-«..     16OOO 

STOKE,  NATURAL  AND  ARTIFICIAL. 

Brick  and  Cement,     ------    28O  to  300 

Glass,  -        -    ;   -        -,        -  .      -        r        -         -  9400 

Slate,       ...-,-        r     9600  to  12800 
Mortar,  ordinary,  50 

ULTIMATE  RESISTANCE   TO    COMPRESSION, 

METALS. 

Brass,  cast,        -        «        *        *         -         -         -        -     103OO 

Iron,     «      .        *        .        *        a        .      82000  to  14500O 

"      wrought,          *        •       •        <  3600O  to  4OOOO 


Ifc  K. 
STRENGTH  OF  MATERIALS. 

(CONTINUED.) 

TIMBER,  SEASONED,  COMPRESSED  IN  THE 
DIRECTION  OF  THE  GRAIN 

Average. 

Ash,  American,         -  4400  to  5800 

Beech,       -  -     5800  to  6900 

Box,     -  10300 

Cedar  of  Lebanon,         -  -         5900 

"     American,  red,  6000 

Deal,  red,     -  -•        6500 

Fir  or  Spruce,  5100  to  6800 

Oak,  American,  white,  -      7200  to  9100 

"    British,  10000 

"    Dantzig,      -  -         7700 

Pine,  American,  white,  -                                     5000  to  5600 

"                           long  leaf,  yellow      -                        -         8000 

Spruce  or  Fir,  5800  to  6900 

Walnut,  black,        -  -         7500 

STONE,  NATURAL   OR   ARTIFICIAL. 


Brick,  weak, 

"      strong, 

"      fire,        - 
Brickwork,  ordinary,  in  cement, 

. "          best, 
Chalk, 
Granite, 
lyimestone, 
Sandstone,  ordinary, 


550  to  800 
1100 
1700 

300  to    450 

1000 

330 

5500  to  11000 

4000  to  11000 

4000 


ULTIMATE  RESISTANCE  TO  SHEARING 


METALS. 
Iron,  cast,          - 
"      wrought,  along  the  fiber, 

TIMBER,  ALONG  THE  GRAIN. 


27700 
45000 


White  Pine,  Spruce,  Hemlock, 
Yellow  Pine,  long  leaf, 
Oak,  European, 
Ash,  American, 


500  to  800 

-      630  to  960 

2300 

-    2000 


362 
/"able  of  Safety  Load  of  Cast  Iron  Columns— Factor  of  Safety  10, 

This  factor  of  safety  of  10  has  been  adopted  to  allow  for  imper- 
fections in  casting;  such  as  air-holes,  unequal  thickness  of  metal, 
•tc.,  devietion  of  pressure  from  axis  of  columns,  and  the  effect  of 
latenal  forces  accidentally  applied.  Where  these  risks  do  not 
occur,  a  factor  of  6  may  be  taken  for  safe  load.  Ends  of  columns 
should  always  be  turned-  true. 


(•q4#ua|  .jo  jooj 
jad  eutur.ip3 
jo  -em  ui  iqS|o& 

55  i!  31522  55253  s:-!^!  :B 

saqooi 
at  va&B  iBuouoag. 

91 

•*  «       CO       :c  »  ®  l>  ^       »%  i^  X  X  t-        9*O7SM>e»        •*  » 

f 

kl 

UI 

u 

M 

1 

c 

| 

:  :      :  :      :  :   :   :   :      :   :  '.   :         ::::::** 

it 
ot 

1 

M  :         :  !  ';  1  N    28 

2 

J 

:   :      '.   :       :''.'.: 

LENGTH  OF'COLUMNS  l*i 

BOTH  EWDB  TUBWRD.  •£ 

91 
94 

| 

:]  \  i   ;=sss  :sssasa  ss 

g 

a! 

COC          r^      91                                                                            A 

at 

s 
fi 

OC99             US       PS 

£'    j 

rcc      ^i-      r. 

_«„„       ^,-919191       9191WSCW*       MM 

- 

1 

S2       £*       2«^CtM       OS^^Ot^       A^XM^X       C.M 

' 

94 

1 

r-o      ee            r. 

^        -^atOM       919J««»       «»^»00       ** 

O 

1 

22   2,   2,Sxg  g5g.5   S!.3S58  5g 

OK. 
(P 

I 

«2     2a»     »^-wto     -«-e9.     ,9«.x*o«     «e» 

I 

.*?     "§ 
«<  i  i?       »  *      «9«et>91r>       «MX«9       »•  3t  W  M  3t  «       O  * 

15                91      9J»8«       •*       «                          10       W           X            » 

bi~     .               .  u  .       - 

;  »»  *w  «*_j  **-..;  *x^s**  xs 

TABLE  OF  SAFETY  LOAD  OF  CAST  IRON 
COLUMNS. 

(CONTINUED.) 


•tuihiai  jo  jooj 

^^  ^    -----      --r  .         1 

en  foju  iBnouooc 

^LENGTH  OF  COLUMNS  IN  FEET. 

|»  |  BOTH  ENDS  TURNED. 

e 
ee 

£_ 
I 

r-3tciec  «?-•:«      -•*««-  -wo      Cii.c-r»es.o      Oso* 

s 

-,s,^.      -*».^      ^      «^^wo      ^          -,cr®^      *xe* 

s 

Jr 

a 

$ 

<N(M9»eBeo«-*    .aieseesewe      so-r^.e.*®.-      ^-ao 

Ot 

M 
•1 

, 

e 

i 

^^^^  9t           „  ^          &      ~ 

•- 

1 

'      CODfM^O        «.        «1        *•                    »        -«~,        ^T«cr 

^^^^.ooo      ^.-h^..^c,t-      .e^.-.-Qc-c-      ec-oe 

CO 

1 

^-..o^^coo      Vke.e««^«>      CD^^XSS*.      -*a 

» 

I' 

£ 

I 

i(5  *«  i-  •?»  GC  «r  d       O  r»  »  »1  CC  ift  OS        Si  OC  t^  iffl  8C  OS  t~       SI  91  "Si 

—             _Z^!!I       —  — 

0 

1 

SS^££§   S;3S«SS^   SSI22I5S   SSS: 

00 

I 

—  OD  i»  *i  SS  ®  S3        M  «  91  —  5:  r-  »       MS»O«®«®»       "r<~ 

'« 

1 

"Itfjajv 

364 


TABLE  OF  SAFETY  LOAD  OF  CAST  IRON 
COLUMNS. 

(CONTINUED.) 


*  -qiJBuai  JO  JOOJ 

'    a  ad  s  u  tun  [03 


EET. 


NGTH-  OF  COLUMNS 

BOTH  ENDS  TURNED 


J±_ 


H^ 


corsxorco 


'•*!  O  <X  t ••  »  «O 


5  OS  CO  **•        «-  -*  —  OS  «ff  «1  3S  r-  —  CO        O 

C  » (5«  r-       CC  5:  —  —  —  X  O       «R  «  —  US  CC  99  88       O  —  O  3>  r»  S 

sssccai     r>I  —  csd-r  —  oJ     o'»oo-^cct»«o     •^ot^oree* 


-CCOSO        CSl-QCOSO«-<iN        I-XOSC—  (M  •*•        OS  O  —  <N  CO  •* 


waoor-      ««J-o^,«-      o^09*,Or^r~OD»0-0 

OOUOOr^        i- Ct- O5  O  —  »»  CO        gjc  OS  O  «  W  "t- «O        OS  O  «-•  1C -»•  CD 


»^09      oOOSOi-i»»99kO      OSOi-i&4e««Sr-      O  — w-^fior. 


c«-«o 


O»t*ke     t^osi^ogio****     O«OS»OCDOS«      ocDoo»-4«e» 


»ie9»or-     Of-ieo^n: 


~OMCOCCG>1CO       GC  M  r-  01  CO  « 


df       1-1  <N  ^*«  U3  CC  QC  •-       Oie9>C 


Crushing  and  Tensile  Strength,  in  Ibs.,  per  square  inch  jf  Natural 
and  Artificial  Stones. 


DESCRIPTION. 

Weight 
per 
Cubic  ft 
tn  Ibs 

Crushing  Force. 
Lbs.  per  Square 
Inch. 

Aberdeen  Blue  Graaite  ..    ..'.. 

16? 

8.400  to  10.914 

Quincy  Granite 

160 

15  300 

Freeetone,  Belleville  .                               .    . 

3  522 

Freestone,  Caen                      .    . 

1  088 

Freestone,  Connecticut. 

3  319 

Sandstone,  Acqula  Creek,  used  for  Capitol  Wash- 
ington                                       

5,340 

Limestone,  Magnestan,  Graf  ton.  Ill  
Marble,  Hastings,  N.  Y   

17.000 

13,941 

Marble,  Italian        

12,624 

Marble,  Stockbrldge,  City  Hall,  N.  Y   .     
Marble,  Statuary  

10,382 
3,216 

Marble,  Veined 

165 

9  681 

Slate  

9,300 

Brick,  Red  ^  T  

135.5 

SOS 

Brick,  Pale  Bed  

130.3 

562 

Brick,  Common 

800  to    t  000 

Brick,  Machine  Pressed 

6  222  to  14  214 

Brick  Stock 

2,1^7 

Brtck-work,  set  In  Cement,  bricks  not  very  hard, 
Brick,  Masonry,  Commou 

521 
500  to     809 

Cement   Portland 

1,000  to  8  309 

Cement,  Portland,  Cement  i.  Band  1    
Cement   Roman 



1,280 
342 

Mortar                                              

120  to  240 

Crown  Gl&M                             .         ;  .... 

31  000 

Portland  Cement  ..  .   

TENSION. 

427  to  711 

Portland  Cement  wHb  Sand 

92  to  284 

Glass  Plate 

9  420 

Mortar 

50 

Plaster  of  Paris  .     ..             

72 

6lme  .-  

11,000 

Capacity  of  Cylindrical  Cisterns.' 


FOR   EACH    FOOT  OF  DEPTH. 


Diameter 
In  Feet. 

Gallons. 

Pounds. 

Diameter 
In  feet. 

Gallons. 

Pound*, 

2.0 
2.5 

23.5 
36.7 

1M 

306 

9.0 
9.5 

475.9 
530.2 

4,421 

3.0 

52.9 

441 

10.0 

587.5 

4,899 

3.5 

72.0 

600 

11.0 

710.9 

5,928 

4.0 

94.0 

784 

12.0 

846.0 

7,054 

4.5 

119.0 

992 

13.0 

992.9 

'  8,280 

5.0 

146.9 

1,225 

14.0 

1,151.5 

9,602 

5.5 

177.7 

1,482 

15.0 

.     1,821.9 

11,023 

6.0 

211.5 

1,764 

20.0 

2,350.  1 

19\596 

6.5( 

248.2 

2070 

25.0 

8.G72.0 

30,820 

7.0 

287.9 

2,401 

30.0 

5,287.7 

44,093 

7.5 

S30.5 

2.756 

35.0 

7,197.1 

60,016 

8.0 

376.0 

3,185 

40.0 

9,400.3 

78,?  as 

8.5 

424.5 

3,540 

366 
PROPERTIES  OF  TIMBER. 

•   •   I  i   !  j  I  \  I  8  n 

'     :     i     :     :     •     :     ;    2    S 

i:  i  !  I    Mi! 


s  |  s   s 

i  -'  I  § 


3      : 

S      : 


2     2 
5    3 


f*    ~    g 

222 


strength 
reftklng. 

e  =  100. 


III 


§  3  s       ?       *  2 '  S  8  5j  i       ?  = 

222§2S222222|3  = 

CMO«rt  S  0?S???!r)>O  «$ 


rushing 
gth  per  eq 
..  In  lt>6. 


|    S    § 

232 

s   §   S 


o      § 


i  I  i 


£  l 


3222 

I  i.  i  s 


2  2  S  5 
|  |  |  | 
d  c«*  a  of 


P    «» 

M        M 


i 


S    2    S 

000 

s   5   i 


-» 

5    3    S 


:  I  U  j  i  I  i  I  I*  * 
j>g  i  Iv  I  i  ••>.-'  3>. "  »J  «;:'  J 
I- 1 :»  I  1  I  *  i .  *  - 1  4l  I  * 

dowan.SsooSa:^^ 


367 

SQUARE  CAST  IRON  COLUMNS. 

Safe  Load  in  Pounds.     Safety  6. 
BOTH  ENDS  TURNED. 


f 

}  4utfllde*5Ue  Column,  8x8. 

LengtL.  [| 

Outride  SizeColBM,  I  Ox  It/ 

•  &in..; 

I  in. 

l&in. 

XHL 

lin. 

Ifein 

8 

255,486 

328,902 

458,113 

10 

325,965 

422,874 

599,07  1 

247,656 

318,822 

444,073 

11 

318,015 

412,560 

684,4** 

10 

289,457 

308,266 

429,370 

12 

309,751 

401,839 

66»,*7t 

231,786 

298,430 

416,670 

13 

301,232 

390,787 

563,61* 

12. 

222,400 

286,308 

898,787 

14 

292,540 

379,512 

687.««* 

1  is 

213,752 

275,176 

888,280 

15 

283,752 

368.111 

521,  7*0  ' 

14 

204,896 

263,774 

267,399 

16 

274,925 

356,669 

505,**?  t 

15 

196,642 

258,153 

252,606 

17 

266,109 

346,229 

4H9,07o 

16 

188,268 

242,368 

337,584 

18 

257,362 

833,876 

472,980 

17 

180,126 

231,887 

322,986 

19 

248;709 

822,660 

457,087 

18 

172,220 

221,709 

808.810 

20 

240,204 

311.616 

441,46ft 

19 

164,589 

211,884 

295,125 

21 

231.878 

300,809 

426,14* 

20 

157,242 

202^,426 

281,950 

22 

223,720 

290.282 

411,16* 

21 

150,225 

193,354 

269,314 

23 

216,881 

280,062 

896,754 

*2 

148,452 

184,674 

257,224 

24 

208,083 

269,946 

382,42f 

23 

137,014 

176,37(i 

245,562 

25 

200,619 

260,263 

368,704' 

£4 

180,881 

168,490 

284,682 

26 

193,398 

250,895 

355,434 

25 

126,849 

160,809 

223,985 

27 

186,411 

241,830 

342,59* 

OatBlde  Site  Column,  12x12. 

Outside  Site  Column,  12x12. 

l.in. 

l&in. 

2  in. 

1  in. 

iKta. 

2  IQ.  V 

12 

616,846 

740,029 

989,720 

21 

414,986 

594,184 

7.>4,52<t 

13 

606.383 

725,048 

980,696 

28 

403.458 

577,678 

7  38,560 

14 

495,550 

709,537 

901,000 

23 

392,093 

561,406 

712,890 

15 

'484,418 

693,598 

880,765 

94 

380,864 

545,328 

692,480 

46 

473,057 

677,382 

860,104 

25 

369.829 

529,527 

•4)72,416 

17 

461,579 

660,888 

839,160 

26 

359.005J  514.030 

652,730 

18 

449,913 

644,194 

818,024 

27 

348.401:  498.847 

683,460 

10 

438,253 

627,409 

796,824 

2ft 

337.7311  483.569 

614,056 

L£ 

426,693 

610,804 

775.684 

29 

3  29,941  j  469.552 

690.S** 

COST  OF  LIVING  IN  CHINA. 
Land  in  China  is  divided  into  more  holdings  than  anjr 
other  land  in  the  world.  It  takes  but  a  very  small  piece  •£ 
land  to  support  a  Chinese  family.  The  Chinese  are  the 
closest  and  most  thorough  cultivators  in  the  world.  Field 
hands  in  China  are  paid  $12  per  annum.  The  food  is 
cooked  by  the  employer.  With  his  food  he  is  furnished 
straw,  shoes  and  free  shaving — the  last  a  matter  which  a 
Chinaman  never  neglects  for  any  great  length  of  time  where 
it  is  possible  to  secure  the  luxury.  It  costs  about  $4  a  year 
to  clothe  a  Chinaman.  Much  of  the  land  ki  China  is  divided 
Up  into  gardens  of  areas  as  small  as  one-sixth  of  an  acre. 


;  NOTES  OX  HOT  WATER  SYSTEMS. 

Let  your  "  risers  "  not  be  less  than  i%",  for  smaller  pipes 
soon  become  coated,  if  the  water  used  contains  lime  or  otner 
matters  in  solution  or  suspension. 

;      Galvanized  pipe  is  best;  it  does  not  become  rusty  and  dis- 
color the  water.' 

In  ordinary  pip?  be  sure  to  get  "  galvanized  steam,"  and 
Hot  "  galvanized  gas. " 

Let  your  draw-off  services  be  for  bath  i",  to  lavatories 
l",  for  hot  water  ]£'.  Do  not  make  the  "  draw-offs "  too 
small,  it  takes  too  long  to  drain  a  pipe  of  cold  water. 

.  The  larger  tire  pip?s  the  freer  the  circulation,  and,  if  you 
have  Hard  water,  they  will  remain  in  good  order  longer. 

;  Be  sure  that  all  joints  are  secure  and  free  from  leaks,  and 
always  look  through  a  pipe  before  fitting  it  in  place,  to  see 
that  there  is  no  dirt  or  impediment  to  the  flow  of  water 
through  it. 

Avoid  the  use  of  elbows  in  circulating  pipes,  use  only 
bends;  if  you  cannot  avoid  using  an  elbow,  see  that  it  is  a 
round  one. 

TO  SOLDER   ALUMINUM. 

M.  Bourbouze  has  formed  an  alloy  of  45  parts  of  tin  and 
55  parts  of  aluminum,  which  answers  for  soldering  aluminum. 
This  alloy  possesses  almost  the  same  lightness  as  the  pure 
aluminum,  and  can  be  easily  soldered.  M.  Bourbouze  has 
invented  another  containing  only  ten  per  cent,  of  tin.  This 
second  alloy,  which  can  replace  aluminum  in  all  its  applica- 
tions, can  be  soldered  to  tin,  while  it  preserves  all  the  prin- 
cipal qualities  of  the  pure  metal. 

A  new  and  curious  alloy  is  produced  by  placing  in  a  clean 
crucible  an  ounce  of  copper  and  an  ounce  of  antimony,  and 
fusing  them  by  a  strong  heat.  The  compound  will  be  hard, 
and  of  a  beautiful  violet  hue.  This  alloy  has  not  yet  beea 
applied  to  any  useful  purpose,  but  its  excellent  qualities, 
independent  of  its  color,  entitle  it  to  consideration. 

A  CHEAP  FILTER. 

A  cheap  filter  which  any  tinner  can  make  is  12x6  inches  ia 
size,  and  8  inches  high.  The  water  flows  in  near  the  top,  and 
»n  the  top  is  a  door  through  which  to  get  into  it  to  clean  H. 
The  outlet  pipe  at  the  bottom  projects  two  inches  up  on  the 
inside  to  hold  the  dirt  back.  A  large  sponge  is  placed  inside, 
which  forms  the  filtering  medium,  which,  of  course,  can  be 
cleaned  as  often  as  desired. 


COMPOSITION  OF  BABBITT  METAL. 

Genuine  Babbitt  metal,  according  to  the  formula  of  the 
inventor,  is  9  of  tin,  i  of  copper.  Antimony  has  been  added 
since,  so  that  the  proportions  by  hundreds  will  stand  80  tin, 
5  copper,  15  antimony.  For  high  speeds  the  metals  should 
be  cooler,  giving  a  larger  proportion  of  tin ;  for  weight  the 
metal  should  be  harder,  giving  a  larger  proportion  of 
antimony. 

THE  HEATING  SURFACE  OF  A  STEAM    RADIA- 
TOR. 

For  instance,  the  radiator  contains  300  feet  of  one-inca 
pipe;  what  will  be  its  heating  surface  in  square  feet?  A. 
300  feet  =3, 600  inches.  The  outside  circumference  of  one- 
inch  pipe=4  inches.  And  3,600  X  4  =  14,400  square  inches 
of  heating  surface.  Lastly, 

14,400 

=  100 

144 

square  feet  of  heating  surface.  The  way  you  have  calculated 
the  heating  surface  is  not  correct,  because  you  did  not  multi- 
ply the  length  of  the  pipe  by  the  circumference. 

A  CHIMNEY  THAT  WILL  DRAW. 

To  build  a  chimney  that  will  draw  forever,  and  not  fill  up 
with  soot,  you  must  build  it  large  enough,  sixteen  inches 
square;  use  good  brick,  mid  clay  instead  of  lime  up  to  the 
comb;  plaster  it  inside  with  clay  mixed  with  salt ;  for  chimney 
tops  use  the  very  best  of  brick,  wet  them  and  lay  them  in 
cement  mortar.  The  chimney  should  not  be1  built  tight  to 
beams  and  rafters;  there  is  where  the  cracks  in  your  chimney 
comes,  and  where  most  of  the  fires  originate,  as  the  chimney 
sometimes  get  red  hot.  A  chimney  built  from  the  cellar  up 
is  better  and  less  dangerous  than  one  hung  on  the  wall, 

ANCIENT  USE  OF  LEAD. 

The  ancients,  like  the  moderns,  used  lead  to  fasten  iron 
into  stone,  to  give  a  glaze  to  pottery,  and  as  a  help  to  the 
manufacture  of  glass.  Very  singular  were  the  "  imprecation 
tablets,  surreptitiously  deposited  in  tombs,  and  sometimes 
even  in  the  coffin  of  the  deceased,  that  a  curse  might  follow 
him  to  the  other  world, '^ which  seem  "to  have  been  more 
frequently  deposited  by  women  than  by  men."  Vitruvius 
describes  elaborately  a  vast  aqueduct,  the  lead  >n  which 


would  cost  to-day  two  millions.  The  leaden  bullets  of  the 
ancient  slingers  often  bore  an  inscription  in  relief  such  as 
4i  Appear,"  "  Show  yourself,"  "  Desist,"  "  Take  this,"  "  Strike 
Rome."  The  Greeks  were  especially  fond  of  bullets  with 
such  mottoes,  and  they  have  been  found  upon  Marathon  and 
many  other  famous  fields. 

A  RUSSIAN   WELDING  PROCESS. 

The  process  of  welding,  invented  by  Mr.  Be  Benardox,  of 
Russia,  is  now  applied  industrially  by  the  Society  for  the 
Electrical  Working  of  Metals.  The  pieces  to  be  welded  are 
placed  upon  a  cast-iron  plate  supported  by  an  insulated  table, 
and  connected  with  the  negative  pole  of  a  source  of  electricity. 
The  positive  pole  communicates  with  an  electric  carbon  in- 
serted in  an  insulating  handle.  On  drawing  the  point  of  the 
carbon  along  the  edges  of  the  metal  to  be  welded,  the  oper- 
ator closes  the  circuit.  He  has  then  merely  to  raise  '.lie  point 
slightly  to  produce  a  voltaic  arc,  whose  high  V  jperature 
melts  the  two  pieces  of  metal  and  causes  them  to  unite.  The 
intensity  of  the  current  naturally  varies  with  the  \\ork  to  be 
done.**  For  regulating  it,  a  battery  of  accumulators  is  used, 
and  the  number  of  the  latter  is  increased  or  diminished  as 
need  be.  This  process  of  welding  is  largely  employed  in  the 
manufacture  of  metallic  tanks  and  reservoirs. 

COLD    SOLDER. 

LaMetallurgie  gives  the  following  receipt  for  cold  solder: 
Precipitate  copper  in  a  state  of  fine  division  from  a  solution 
of  sulphate  of  copper  by  the  aid  of  metallic  zinc.  Twenty 
or  thirty  parts  of  the  copper  are  mixed  in  a  mortar  with  con- 
centrated sulphuric  acid,  to  which  is  afterward  added  seventy 
parts  cf  mercury,  and  the  whole  triturated  with  the  pestle. 
The  amalgam  produced  is  copiously  washed  with  water  to  re- 
move the  sulphuric  acid,  and  is  then  left  for  twelre  hours. 
When  it  is  required  for  soldering,  it  is  warmed  until  it  is 
about  the  consistency  of  wax,  and  in  this  state  it  is  applied 
to  the  joint,  to  which  it  adheres  on  cooling. 

TO  TIN  MALLEABLE  IRON. 

W.  M.  writes :  I  tin  malleable  iron,  which  comes  from  the 
bath  nice  and  bright,  but  although  I  keep  it  covered,  after  a 
few  days  it  gets  red,  copper  colored  in  spots,  and  this  color 
gradually  spreads  all  over  the  work.  Can  you  tell  me  the 
cause  ?  A  — The  red  color  is  probably  derived  from  oxida- 


tion  of  the  iron  by  the  acid  left  in  the  poies  of  thr  iron. 
The  acid  rusts  the  iron  and  oozes  out  through  the*  pores  of 
the  tin  by  the  pressure  due  to  increase  of  bulk  by  tiic  action 
yf  the  acid  upon  the  iron ;  possibly  also  moisture  may  be 
ibsorbed  by  the  acid  through  the  tin,  which  is  porous. 
Rinse  the  work  immediately  after  tinning  in  boiling  water, 
holding  2  oz.  sal  soda  to  the  gallon  in  solution. 

OLD  TINS  NO  LONGER  USELESS 

A  number  of  people  recently  gathered  at  the  Colun.l't 
rolling  mill,  Fourteenth  street  and  Jersey  avenue.  Jersey  City, 
at  the  formal  opening  of  the  mill.  The  industry  is  a  novel 
one,  being  the  manufacture  of  taggers'  iron  from  old  tin  cans, 
and  other  waste  sheet  metal.  This  iron  has  heretofore  been 
manufactured  almost  exclusively  in  Europe,  and  the  Columbia 
Rolling  Mill  Company  is  the  only  American  company  which 
turns  out  the  product  in  large  quantities.  The  process  is 
simple.  The  tin  cans  are  first  heated  in  an  oven  raised  to  a 
temperature  of  about  1,000°,  which  melts  off  the  tin  and  lead. 
The  sheet  iron  which  remains  is  passed  first  under  rubber- 
coated  rollers,  and  then  chilled  iron  rollers,  which  leaves  the 
sheet  smooth  and  flat.  After  annealing  and  trimming,  they 
are  ready  for  shipment.  The  tin  and  lead  which  is  melted 
from  the  cans  is  run  into  bars,  and  is  also  placed  upon  the 
market.  All  the  raw  material  used  is  waste,  but  the  sheet 
iron  turned  out  is  said  to  be  of  good  quality.  It  is  used  for 
buttons,  tags,  and  objects  of  a  like  nature.  The  material  used 
costing  little,  and  the  demand  for  taggers'  iron  being  consider- 
able, it  is  thought  that  this  is  a  good  opportunity  to  build  up 
another  American  industry. 

LEAD  ON  ROOFS  AND  IN  SINKS. 

Tenacity  is  very  slight  in  some  of  the  metals.  An  in- 
stance may  be  seen  where  roofs  are  covered  with  lead.  The 
heat  of  the  sun  will  expand  them,  and,  of  course,  it  is  easier 
for  the  sheets  to  expand  down-hill  than  up;  then,  when  they 
get  cold,  their  own  weight  will  be  too  great  for  them,  and 
they  will  sooner  stretch  than  creep  back  up  hill;  so,  in  fact, 
unless  properly  laid,  the  lead  roof  will  to  some  extent  crawl 
off  its  frame- work.  The  same  thing  will  be  seen  in  kitchen 
sinks  of  lead,  where  very  hot  water  is  run  into  them.  The 
lining  gets  wrinkled,  because,  after  buckling  by  reason  of  the 
expansion,  it  will  sooner  pull  thinner  than  come  back  to  the 
ordinary  position  and  condition  of  surface. 


37* 
,THE  USE  OF  THE  STEEL  SQUARE. 

The  standard  steel  square  has  a  blade  24  inches  long  and  2  inches 
wide,  and  a  tongue  from  14  to  18  inches  long  and  \Y2  inches  wide. 
The  blade  is  exactly  at  right  angles  with  the  tongue,  and  the  angle 
formed  by  them  an  exact  right  angle,  or  square  corner.  A  proper 
square  should  have  tke  ordinary  divisions  of  inches,  half  inches, 
quarters  and  eighths,  and  often  sixteenths  and  thirty-seconds. 
Another  portion  of  the  square  is  divided  into  twelfths  of  an  inch; 
this  portion  is  simply  a  scale  of  12  feet  to  an  inch,  used  for  any  pur- 
pose, as  measuring  scale  drawings,  etc.  The  diagonal  scale  on  the 
tongue  near  the  blade,  often  found  on  square?,  is  thus  termed  from 
its  diagonal  lines.  However,  the  proper  term  is  centesimal  scale, 
for  the  reason  that  by  it  a  unit  may  be  divided  into  100  equal  parts, 
and  therefore  any  number  to  the  icoth  part  of  a  unit  may  be  expressed. 
In  this  scale  A  B  is  one  inch;  then,  if  it  be  required  to  take  off  73-100 
inches,  set  one  foot  of  the  compasses  in  the  third  parallel  under  i  at 
E,  extend  the  other  foot  to  the  seventh  diagonal  in  that  parallel  at  G, 
and  the  distance  between  E  G  is  that  required,  for  E  F  is  one  inch  and 
F  G  73  parts  of  an  inch. 

Upon  one  side  of  the  blade  of  the  square,  running  parallel  with  the 
length,  will  be  found  nine  lines,  divided  at  intervals  of  one  inch  into 
sections  or  spaces  by  cross  lines.  This  in  the  plank,  board  and 
scantling  measure.  On  each  side  of  the  cross  lines  referred  to  are 
figures,  sometimes  on  one  side  of  the  cross  line,  and  often  spread 
over  the  line,  thus,  i  |  4 — 9  |  —  We  will  suppose  we  have  a  board  12 
feet  long  and  6  inches  wide.  Looking  on  the  outer  edge  of  the  blade 
we  find  12;  between  the  fifth  and  sixth  lines,  under  12,  will  be  found  12 
again ;  this  is  the  length  of  the  board.  Now  follow  the  space  along 
toward  the  tongue  till  we  come  to  the  cross  line  under  6  (on  the  edge 
of  the  blade),  this  being  the  width  of  the  board;  in  this  space  will  be 
found  the  figure  6  again,  which  is  the  answer  in  board  measure,  viz., 
six  feet. 

On  some  squares  will  be  found  on  one  side  of  the  blade  9  lines, 
and  crossing  these  lines  diagonally  to  the  right  are  rows  of  figures,  as 
seven  is,  seven  25,  seven  33,  etc.  This  is  another  style  of  board 
measure  and  gives  the  feet  in  a  board  according  to  its  length  and 
width. 

In  the  center  of  the  tongue  will  generally  be  found  two  parallel 
lines,  half  an  inch  apart,  with  figures  between  them;  this  is  termed 
the  Brace  Rule.  Near  the  extreme  end  of  the  tongue  will  be  found 
24-24  and  to  the  right  of  these  33.95.  The  24-24  indicate  the  two 
sides  of  a  right-angle-triangle,  while  the  length  of  the  brace  is  indi- 
cated by  33.95.  This  will  explain  the  use  of  any  of  the  figures  in 
the  brace  rule.  On  the  opposite  side  of  the  tongue  from  the  brace 
rule  will  generally  be  found  the  octagon  scale,  situated  between 
two  central  parallel  lines.  This  space  is  divided  into  intervals  and 
numbered  thus:  10,  20,  30,  40,  50,  60.  Suppose  it  becomes  neces- 
sary to  describe  an  octagon  ten  inches  square;  draw  a  square  ten 
inches  each  way  and  bisect  the  square  with  a  horizontal  and  per- 
pendicular center  line.  To  find  the  length  of  the  octagon  line, 
place  one  point  of  the  compasses  on  any  of  the  main  divisions  of  the 
scale  and  the  other  leg  or  point  on  the  tenth  subdivision. 


373 

ENDLESS  TIN  PLATES. 

A  patent  has  been  recently  granted  for  a  novel  process  of 
manufacturing  continuous  tin  plates.  The  plates  are  made 
of  steel,  and  the  process  consists  of  producing  a  sheet  of 
sbeel  of  any  continuous  length  and  of  required  width,  by 
first  rolling  the  metal  hot  and  afterward  rolling  it  cold, 
until  a  proper  thickness  and  perfectly  smooth  surface  is 
obtained.  Next,  the  surface  of  the  sheet  is  scoured,  and 
then  it  is  afterward  passed  through  a  bath  of  molten  tin, 
thus  receiving  its  coating.  Finally  the  sheet  is  subjected  to 
a  rolling  operation,  under  heavy  pressure,  between  highly 
polished  rolls,  by  which  the  tin  and  steel  are  condensed  and 
consolidated  together,  and  the  surface  hardened  and  pol- 
ished. The  inventor  states  that,  by  this  method,  the  tin 
will  be  found  to  be  so  hardened  upon  and  incorporated  with 
the  steel,  as  to  produce  a  tin  plate  which  is  superior,  in  most 
respects,  to  any  tin  plate,  wherever  produced. 

HARDWARE  IN  HAVANA. 

The  annual  value  of  the  imports  into  Havana  of  iron- 
mongery and  hardware  is  about  $600,000,  of  which  England 
supplies  barely  one-half.  Consul-General  Crowe  states  that 
German  trade  in  these  branches  is  constantly  increasing,  but 
so  far  has  been  confined  to  such  articles  as  white  metal  spoons 
and  forks,  locks,  cutlery  and  wire  nails,  which,  however, 
form  an  important  aggregate,  as  the  consumption  is  consider- 
able. The  German  goods  are  generally  inferior  to  the 
English,  which  are  often  of  better  quality  than  is  actually 
required.  German  travelers  pay  more  frequent  visits,  offer 
better  terms,  and  give  more  attention  to  the  requirements  of 
the  country  than  the  representatives  of  English  firms.  The 
United  States  supplies  barbed  fence  wire,  cut  nails,  carpenter's 
tools,  wheelbarrows,  bolts  and  padlocks,  and,  according  to 
the  British  Consul-General,  "inferior  gas  and  water  valves. " 
Their  pumps  and  plows  are  described  as  superior  to  the 
European  articles. 

CRYSTALLIZED  TIN  [PLATE. 

Crystallized  tin  plate  has  a  variegated  primrose  appear- 
ance, produced  upon  the  surface  by  applying  to  it,  in  a 
heated  state,  some  dilute  nitre-muriatic  acid  for  a  few  sec- 
onds, then  washing  it  with  water,  drying,  and  coating  it 
with  lacquer.  The  figures  are  more  or  less  diversified,  ac- 
cording to  the  degree  of  heat  and  relative  dilution  of  the 
acid.  Place  the  tin  plate,  slightly  heated,  over  a  tub  of 


water,  and  rub  its  surface  with  a  sponge  dipped  iu  a  liquid 
composed  of  tour  parts  of  aquafortis  und  two  of  distilled 
water,  holding  one  common  sale  or  sal-ammoniac  in  solution. 
When  the  crystalline  spangles  seem  to  be  thoroughly  brought 
out,  the  plate  must  be  immersed  in  water,  washed  either  with 
a  feather  or  a  little  cotton,  taking  care  riot  to  rub  off  the 
film  of  tin  that  forms  the  feathering,  forthwith  dried  with  a 
low  heat,  and  coated  with  a  lacquer  varnish,  otherwise  it  loses 
its  luster  in  the  air.  If  the  whole  surface  is  not  plunged  at 
once  in  cold  water,  but  is  partially  cooled  by  sprinkling  water 
*l  it,  the  crystallization  will  be  obtained  by  blowing  cold  air 
•hrough  a  pipe  on  the  tinned  surface,  while  it  is  just  passing 
from  the  fused  to  the  solid  state. 

USEFUL  RECIPES. 

Tinning  Acid  for  Zinc  or  Brass.— Zinc.  3  oz.;  muriatic  acid, 

1  pt.    Dissolve,  and  add  1  pt.  water  and  1  oz.  sal-ammoniac. 
To  Solder  Brass  Easily. —Cut  out  a  piece  of  tin  foil  the  size 

of  the  surface  to   be  soldered.    Then  apply  to  the  surface 
a  solution  of  sal-ammoniac  for  a  flux.    Place  the  tin  foil 
between  the  pieces,  and  apply  a  hot  soldering-iron  until  the 
tin  foil  is  melted. 
To  Solder  Without  /Tea/.— Steel  filings,  2  oz. ;  brass  filings, 

2  oz. ;  fluoric  acid,  1  ^  oz.    Dissolve  the  filings  in  the  acid, 
and  apply  to  the  parts  to  be  soldered,  having  first  thoroughly 
cleaned  the  parts  to  be  connected.    Keep  the  fluoric  acid  in 
earthen  or  lead  vessels  only. 

To  Tin  Brass  and  Copper.— Make  a  mixture  of  3  Ibs.  cream 
of  tartar.  4  Ibs.  tin  shavings,  and  2  gallons  water,  and  boil. 
After  the  mixture  has  boiled  sufficiently,  put  in  the  articles 
to  be  tinned,  and  continue  the  boiling.  The  tin  will  be  pre- 
cipitated on  the  articles. 

TO  POLISH  NICKEL-PLATE. 

To  brighten  and  polish  nickel-plating  and  prevent  rust, 
apply  rouge  with  a  little  fresh  lard  or  lard  oil  on  a  wash- 
leather  or  piece  of  buckskin.  Rub  the  bright  parts,  using 
as  little  of  the  rouge  and  oil  as  possible:  wipe  off  with  a 
clean  rag  slightly  oiled.  Repeat  the  wiping  every  day,  and 
ttoe  polishing  as  often  as  necessary. 


375 


PATTERN  FOR  FLARING  OVAL  ARTICLES. 

Of  all  the  great  variety  of  patterns  with  which  the  tin  man 
has  to  deal,  t^ere  is  probably  none  that  seems  more  difficult 
and  c^u  :cs  mere  troub'e  and  perplexity  to  make  than  a  flaring 
oval  pan.  By  following  the  annexed  diagrams  and  explana- 
tions, the  development  of  this  pattern  will  be  seen  to  be  sim- 
ple, easy  and  quickly  per- 
formed. 

First,  always  describe  the 
oval  from  two  centers  —  thus 
making  the  bottom  of  the  dish 
—  parts  of  two  diameters  or. 
circles.  Separate  the  circles 
when  they  intersect  each  other, 
and  proceed  the  same  as  in  any 
roiu  d,  flaring  article. 

Jn  Fig.  i  the  compasses 
are  set  at  a  a,  and  the  large  circles  described  as  A  A  B  B,  then 
set  the  compasses  at  b  b  and  describe  the  smaller  circles,  thus 
completing  the  oval  or  bottom  of  pan. 

To  make  the  pattern  for  the  body  :  In  Fig.  2  mark  A  B 


the  size  of  large  diameter.     Then  draw  the  depth  of  vessel 
and  flare  desired,  as  A  B  C  D.     Extend  the   lines  C  A  ant 


376 

D  B  until  they  cross  at  e,  set  the  compasses  at  <*,  and  "describe 
the  curved  lines  C  D  and  A  B.  Make  the  length  A  F  equal 
to  A  A  in  Fig.  i.  Add  the  locks  as  shown  in  dotted  lines; 
this  will  be  the  pattern  for  side  of  dish. 

In  Fig.  3,  make  a  a  equal  to  the  small  diameter  and  pro- 
ceed the  same  as  in  Fig.  2,  this  will  be  the  end  pattern.  It 
takes  two  pieces  of  the  large  pattern  and  two  of  the  small  to 


FIG  4. 

make  the  dish.  Should  it  be  found  desirable  to  make  the 
body  of  pan  in  only  two  pieces,  then  cut  the  smaller  or  end 
pattern  in  two  and  place  it  upon  each  side  of  the  large  pattern^ 
as  shown  in  Fig.  4. 

An  oval  can  be  made  from  three  or  more  centers  upon  the 
same  plan  when  desired. 

FLARING   ARTICLES   WITH   ROUND  CORNERS. 

First,  to  cut  the  pat- 
tern of  an  oblong  %r_ 
ing  dish  with  square- 
cornered  bottom  and 
round  cornered  top, 
in  two  pieces,  of  which 
Fig.  I  is  the  ground 
plan,  and  Fig.  2  the 
side  elevation. 

The  height  of  side 
A,  Fig.  2,  is  from  a  to 
bt  which  is  also  the 
radius  for  the  corners. 
First  mark  off  the  side 
A,  Fig.  3 ;  then  strike 
the  segments  of  thecircles  a  b;  this  gives  the  corner.  Then 


377 

murk  off  £>ne-half  of  end  on  each  side  of  a  b  (c  and  </),  whicfc 
completes  the  pattern  for  pj 

one-half  the  dish; 

Fig.  4.  For  practice, 
we  will  now  cut  the  pat- 
tern so  the  bottom,  sides 
and  corners  will  be  in  one 
piece. 

One  end  of  the  seam 
comes  on  the  end  piece, 
and  on  the  other  end  in 
the  center  of  the  corner  piece. 

Fig.  5,  B,  shows  cone  made  by  putting  together  the  two 
flaring  sides  shown  in  Fig.  2,  A  and  C,  the  pattern  required 
to  construct  said  cone  D  is  the  ground  plan  of  cone  B 


divided  into  four  parts.  It  will  be  noticed  that  the  four  cor- 
ners in  Fig.  I  wrill  make  D,  and  that  the  pattern  for  the  four 
corners  (a  b  A,  Fig.  3)  are  equal  to  C,  Fig.  5. 

As  each  corner  of  Fig.  i 
is  one-fourth  of  a  cone,  so 
the  pattern  of  each  corner, 
Fig.  4,  is  one-fourth  of  the 
pattern  C,  required  to  make 
the  cone  B?  Fig.  5, 

We  will  now   suppose  A, 
Fig.  2,  to  be  the  side  view 
of    a    triangular     dish    con- 
structed    on    the  same    prfnciciple     as   A.       Each   of    the 


37* 

sides  will  be  the  same  size  as  required  to  make  the  square  dish. 
only  the  pattern  C,  Fig. 
5,  will  be  required  to  be 
divided  into  three  parts 
for  each  corner  of  the 
triangle.  Fig.  6  is  a 
ground  plan  of  bottom 
of  dish.  We  will  cut  this 
pattern  in  one  piece  by 
marking  off  one  of  the 
rides,  and  then  transfer- 
ing  one-third  of  pattern 
Fig.  8. 


A,  Fig.  7,  to  each 
side,  until  we  have 
used  the  three  sides 
and  three  corner 
pieces. 

The  next  step  will 
be  to  cut  the  pattern 
of  a  flaring  oblong 
dish,  top  and  bottom 
having  round  cor- 
ners, of  which  Fig.  2 
will  be  a  side  view 
and  A,  Fig.  8,  the 
ground  plan. 

If  the  side  and  end 
pieces  in  A,  Fig.  8t 
were  removed,  B 
would  be  the  result. 
C  is  a  side  view  and 
pattern  for  B.  Now, 
if  we  wish  a  pattern 
for  the  A,  all  that  is 
required  is  to  cut  the  pattern  for  the  four  corners  (C)  into  four. 


379 

pieces,  and  place  the  side  and  end  pieces  between,  or,   if  the 
Fig.  9. 


pattern  is  wanted  in  two  pieces, 
take  a  side  on  which  we  place  two 
corners  and  a  half  of  911  end 
against  each  corner,  as  follows: 

Or  we  can  suppose  Fig.  10,  B? 
to  be  the  side  view  of  dish  having 
half-round  flaring  ends,  but  ends 
of  different  diameters,  as  shown 
by  Fig.  10,  A. 

We  will  have  the  small  end 
the  same  as  in  Fig.  8,  so  as  to  use 
the  same  pattern. 

B,  Fig.  10,  showing  side  view 
and  radius  of  large  and  small  \  / 

circle. 

Fig.  10,  C,  giving  the  pattern  for  one-half  of  A,  Fig.  10. 

To   have    the  drawings   appear    plain,   locks    were    not 
added. 

MAKING  EAVE  TROUGH. 

The  outside  line  on  the  larger  of  the  two  small  diagrams 

represents   a   No.    9 
v  .^^__L_^^  spring    wire    clamp, 

V^L                        //^?':":"^":=:x\\  °ne   t0    be    USe(*  at 

\C)|                 f/f,                    \\  eac^   seam   °f  tue 

III                          Yr-|  trough,      The    dark 

^==J\                  III V9\  line  on  outside  of  the 

jt^_^                          _  1  smaller  diagram  rep- 

^^^  resents  a  small  clamp 

used  to  hold   the   bead  down  at  the  ends  of  the  log.     The 


log  with  it  3  trough  cia':>pt;vl  u,>  u. 
d  to  the  flat  side 


large  diagram  shows  the 

It  will  be  seen  that  a  j^-inch  piece  is  secured 

of  the  log,  which  piece  projects  }£  ur   in  inch  beyond  one  edge 


of  the  log.  A  rocker  may  also  be  placed  under  the  log. 
The  log  is  secured  to  the  bench  by  hooks  or  staples  with  a 
long  shank  fastened  to  the  bench  and  hooking  onto  spikes 
driven  intov  the  ends  of  the  log. 


TABLE  OF  HEIGHT  OF  ELBOW  ANGLED. 

The  following  table  gives  the  height  of  pitch  of  miter 
lines  for  elbows  from  one  inch    to    twenty-five    inches    in 

diameter.     It  will   be 
found  of  great   assist  - 

"      ibl--p  - 

bow   patterns  quickly 
"y,  by  do- 


ance  in  describing  el- 
bow patterns  c 
and  accurately, 
ing  away  with  draw- 
ings and  geometrical 
calculations,  which 
would  otherwise  be 
necessary  to  get  the 
correct  pitch  of  elbows. 
The  accompanying  dia- 
gram indicates  the  po- 
sition of  base  and 
miter  lines.  The 
height  of  pitch,  that 
is,  the  length  from  O 
to  W,  is  shown  by  the  table  for  all  elbows  from  one  inch  to 
twenty-five  inches  in  diameter,  and  of  from  two  to  ten 
pieces.  In  two-piece  elbows  the  height  of  pitch  is  the  diam- 
eter of  the  elbow,  and  this  column  is  added  to  make  the 
table  complete.  No  matter  how  large  the  sweep  of  an  el- 
bow, the  angle  of  pitch  remains  the  same,  and  the  only  dif- 
ference to  be  made  in  cutting  the  pattern  is  to  add  space  as 
desired,  as  indicated  at  X  in  the  diagram.  Locks  and  seams 
are  to  be  added. 


•Sj 

NO.    OF   PIECES    IN   ELBOW. 

II 

2 

3 

4 

5 

6 

7 

8 

9 

10 

I 

I 

7-16 

9-32 

7-32 

6-32 

5-32 

i-8 

1-8 

3-32 

2 

2 

27-32 

18-32 

11-32 

9-32 

1-4 

7-32 

6-32 

3 

3 

13-16 

l-f 

1-2 

7-16 

11-32 

5-16 

9-32 

4 

4 

i  21-32 

i     1-16 

13-16 

21-32 

9-16 

15-32 

13-32 

3-8 

5 

5 

2       I-l6 

i     5-16 

13-16 

11-16 

9-16 

1-2 

7-16 

6 

6 

2       1-2 

i     5-8 

i     3-16 

31-32 

13-16 

11-16 

5-8 

9-16 

7 

7 

2    29-32 

T     7-8 

3-8 

i     1-8 

15-16 

13-16 

9-16 

5-8 

8 

8 

3     5-16^     1-8 

9-16 

i     1-4 

i     1-16 

29-32 

13-16 

23-32 

9 

9 

3  23-32 

2  13-32      13-16 

i     7-16.1     3-16  i 

29-32 

13-16 

10 

10 

4     1-8 

2    II-l6 

i     9-16       5-16,1     1-8 

29-32 

ii 

ii 

4     1-2 

2    15-16'          3-16 

i     3-4 

7-16  i     1-4 

3-32 

i 

12 

12 

4  15-163     3-16        3-8 

i     7-8 

9-16  i     3-8 

3-16 

i     1-16 

13 

13 

5     3-8 

3     7-8          9-16  2     1-16 

23-32  i  15-32 

5-i6 

i     5-32 

14 

14 

5     3-4 

3  23-32(       3-4    2     7-32 

7-8 

i     9-16 

3-8 

i     1-4 

15 

15 

6     5-32 

4                 3I-32J2     3-8 

i  11-16 

1-2 

i  11-32 

16 

16 

6  19-32 

a.     1-4 

3     5-32  2  17-32 

1-8 

i  13-16 

19-32  I       7-16 

17 

17 

7 

4     7-32 

3     6-162  11-16 

i  15-16 

11-161     1-2 

18 

18 

7     3-8 

4  25-32 

3     9-162  27-32 

3-8 

2       1-32 

25:321  19-32 

19 

10 

5     1-163     3-4 

3 

1-2 

2       1-8 

7-8 

i  11-16 

20 

20 

8     1-4 

5     5-163  31-32  3     3-16 

21-32  2       1-4 

i  25-32 

21 

21 

8     5-8 

5   19-324     5-323   11-32 

13-162      3-8 

1-161     7-8 

22 

22 

9     1-16 

5  27-32  4     3-8    3     1-2 

I5-l62       1-2 

3-16.1  15-16 

23 

2} 

9     7-166     3'3?'4     9-163  21-32 

3     1-16  2  10-32 

9-32  2       1-32 

24 

24 

9     7-8 

6     3'8    4     3-4  '3  i3-i6 

3     3-162  11-16 

3-8 

2       1-8 

25 

2510        9-32 

6     5-8    4  15-163  15-16 

3     5-162  13-16 

7-162     3-16 

1 

1 

The  table  is  adapted  to  right-angled  elbows  only.  The 
line  of  figures  at  the  top  of  the  table  indicate  the  number  of 
pieces  of  which  elbows  are  to  be  made.  All  other  figures  are 
in  inches,  the  first  or  left  hand  column  being  the  diameter  of 
elbows,  the  remaining  column  being  the  height  of  pitch 
required. 

ZINC  AS  A  FIRE  EXTINGUISHER. 

Zinc,  placed  upon  the  stove,  in  fire  or  in  grate,  is  said  to 
have  proved  itself  an  effective  extinguisher  of  chimney  fires. 
To  a  member  of  the  Boston  Fire  Department  is  reported  to 
be  due  the  credit  of  successfully  introducing  this  simple 
scheme.  When  a  fire  starts  inside  a  chimney,  from  whatever 
cause,  a  piece  of  tin  sheet  zmc,  about  four  inches  square,  is 
merely  put  into  the  stove  or  grate  connecting  with  the  chim- 
ney. The  zinc  fuses  and  liberates  acidulous  fumes,  which, 
passing  up  the  flue,  are  said  to  almost  instantly  put  out  what- 
ever fire  may  be  there.  It  certainly  sounds  simple  enough. 


3S2 

HOME-MADE  ASH  SIFTER. 

An  io\va  correspondent  sent  Good  Housekeeping  the  fol- 
lowing diagram  and  description  of  a  home-made  ash-sifter, 
any  tinner  or  other  person  may  construct :  "  I  got  my  idea  of 

it  from  seeing  sand  sifted  by 
throwing  it  on  a  sieve  that 
stood  slanting.  The  wire 
sieve  (already  wove)  can 
be  bought  at  a  hard- 
ware store  for  twenty 
cents  a  running  foot,  and  it 
is  two  or  two  and  a  half 
feet  wide,  and  this  can  be 
tacked  to  a  frame  made  to 
fit  the  sifter,  one  end  just 
reaching  over  the  box  for 
coal,  and  the  other  end  ex- 
tending nearly  to  the  top 
of  the  sifter.  There  is  no 
shaking,  nor  any  dust. 
Ashes  are  emptied  in  the 
top  of  the  sifter,  the  coal 
being  carried  over  the  sieve  to  the  coal  box,  while  the  ashes  go 
through  into  the  ash  box.  The  sieve  should  be  two  and  a 
half  feet  long.  Can  use  a  sliding  or  swinging  cover." 

TO  DESCRIBE  A  MITER. 

As  there  seems  to  be  some  interest  manifested  in  regard  to 
tbj  miter  question,  and  nothing  definite  as  to  the  desired 
miter  lias  been  given,  I  wish  to  submit  the  following  rule: 

Let  a  in  diagram  be  the  size  of  the  article  upon  which  the 
miter  is  to  be  cut  ;  strike  a  circle  full  size,  or  from  edge  to 
edge  as  shown  at  e  and  b  of  the  diagram ;  draw  a  line  as 
shown  by  </,  from  e  to  b>  which  divides  the  circle  equally.  If 


you  wish  a  square  miter  set  compass  at  e  and  obtain   one- 
fourth  of  the  circle  as  shown  at  figure  2,  and  draw  line  b  f 


3^3 

intersecting  trie  circle  where  the  p  >int  of  the  compass  shows 
one-fourtu  of  circle.  Cutting  this  line  you  have  a  s  juare 
miter.  Sho.ild  you  wish  your  work  to  form  six  squares,  take 
the  sixth  of  a  circle  as  shown  at  figure  i  by  line  c  b  ;  or,  if 
eight  squares,  one-eighth  f  circle,  and  intersect  the  circle  at 
point  designated  by  compass. 

A  miter  may  be  cut  for  any  angle  desired  by  the  same 
rule ;  divide  the  circle  into  the  number  of  squares  wanted, 
and  proceed  a>  shown  above.  This  rule  does  not  apply  to 
forming  a  miter  for  gutters. 


TO  PESCRIBE  A  PATTERN  FOR  A  FOUR-PIECE 
ELBOW. 

Three  and  four  piece  elbows  have  very  largely  taken  the 
;  old  right-angled  elbow,  on  account  of  their  bet- 
ter appearance,  and  also 
becajse  they  lessen  ob- 
struction to  draft.  The 
machine-made  article  is 
k  pt  in  stock  for  all 
common  sizes,  but  the 
'inner  is  liable  to  be 
called  upon  at  anytime 
to  make  such  an  elbow, 
on  account  or  stock  be- 
ing sold  out  or  of  un- 
usual size,  or  other 
cause.  Herewith  are 
given  diagrams  and  ex- 
planations which  will 
enable  any  tinner  t^ 
construct  a  pattern  for 
any  desired  size. 

Let  AB  E  D,Fig.  i, 
be    the    given    elbov 


A98  7 


ft     4.    821B 


draw  the  line  F  C  ;  make  F  M  equal  in  length  to  one-half 
the  diameter  of  the  elbow,  with  F  as  a  center ;  describe  the 
arc  K  L  ;  divide  the  arc  K  L  into  three  equal  parts ;  draw 
the  lines  F  H  and  F  I ;  also  the  line  I  H  ;  divide  the  section 
H  K  into  two  equal  parts,  and  draw  the  line  F  G ;  draw  the 
lins  A  B  at  right  angles  to  B  C ;  describe  the  semi-circle. 
A  N  B  ;  div'^~  +he  semi-circle  into  any  number  of  equal 
parts;  from  me  points  draw  lines  parallel  to  B  C,  as  I,  2,  5, 
etc. 


3*4 

Set  off  the  line  ABC,  Fig.  2,  equal  in  length  to  the  cir- 
cumference of  elbow  A  B  ;  erect  the  lines  A  F,  B  D  and 


C  E  ;  set  off  on  each  side  of  the  line  B  D  the  same  number 
of  equal  distances  as  in  the  semi-circle  A.  N  B ;  from  the 
points  draw  lines  parallel  to  B  D,  as  i,  i,  2,  2,  etc.  ;  make 
B  D  equal  to  B  G ;  make  A  F  and  C  E  equal  to  A  J  ;  also 
each  of  the  parallel  lines,  bearing  the  same  number  as  i,  i, 
2,  2,  3,  3,  etc.  ;  then  a  line  traced  through  the  points  will 
form  the  first  section  ;  make  F  G  and  E  J  equal  to  H  I  ;  re- 
verse section  No.  i  ;  place  E  at  G  and  F  at  J  ;  trace  a  line 
from  G  to  J  ;  make  G  H  and  J  I  equal  to  P  6,  Fig.  67,  or 
to  D  K.  Fig.  68;  take  Sec.  No.  i,  place  F  at  H  and  E  at 
i,  and  trace  a  line  from  H  to  I ;  this  forms  Sec.  No.  3 
and  4. 

Edges  to  be  allowed. 


In  the  West  Indies  the  work  of  coaling  ships  is  performed 
by  negresses.  Like  ants  going  to  and  fro,  each  of  these 
women,  with  a  load  of  coal  weighing  about  forty  pounds, 
carried  in  a  basket  on  top  of  the  head,  climbs  the  eang-piank, 
and  the  bunkers  are  filled  in  a  wonderfully  short  time.  For 
this  arduous  work,  a  cent  a  basket  is  the  general  price,  but 
night  work  and  emergencies  double  the  rate.  A  penny  is 
given  to  each  woman  as  she  fills  her  basket,  and  the  number 
given  out  forms  a  check  on  the  tally  kept  by  the  parties 
receiving  the  coal.  The  name  of  the  firm  owning  the  coal 
pile  is  stamped  on  the  coins,  which  are  current  throughout  the 
:  slands. 


3*5 
A  WIRE  FLOWER  STAND. 

Tinners  are  ingenious,  and  can  generally  make  anything 
from  sheet  metal,  wire,  or  other  light  material,  which  tliey 
take  a  fancy  to  try  their  hands  at.  Many  have  made  orna- 
mental articles  at  il'i 
moments  with  which  to 
beautify  their  own  home, 
or  possibly  that  of  some 
young  lady.  By  their 
skill  in  thi^  direction 
they  ore  frequently  able 
to  make  presents  yi  arti- 
cles of  their  own  make, 
which  are  not  merely  or- 
namental, but  also  useful. 
This  is  commendable, 
and  such  eki!!  and  enter- 
prise is  wo/thy  Of  encour- 
agement. 

We  here  present  an 
illustration  of  a  new 
round  flower-stand  con- 
structed in  three  j  arts, 
which  can  be  take;*  asun- 
der so  as  to  convert  the 
stand  at  will  into  a  rustic 
table.  The  cut  is  taken  from  the  London  Ironmonger^ 
which  says  that  the  originator  of  the  flower-stand  is  doing 
well  with  it. 

TO  STRIKE  AN  OVAL  OF  ANY   LENGTH  OR 
WIDTH 

In  arecet't  number  of  the  American  Ar  isan,  which  I 
have  mislaid,  some  one  asks  for  a  rule  to  stride  nn  oval  of 
any  desired  width  and  length.  There  are  several  different 
ways  of  striking  an  oval  or  ellipse,  but  I  find  the  one  1  en- 
close you  the  most  practical. 

Let  A  B  and  C  D  equal  width  jind  length.  On  the  line 
CD  lay  off  the  width  of  oval  a:  C  C.  Divide  the  distance 
from  E  to  D  into  thr  e  equal  parts,  and  lay  off  two  of  the 
parts  thus  formed  on  either  s'de  of  the  center  F,  as  G  and 
H.  Span  the  dividers  from  H  to  G,  and,  with  F  as  a  center, 
check  the  line  A  B,  as  at  M  and  K.  Draw  1'ne  intersecting 
the  points  H  M  G  K,  and,  with  tin*  radius  G  D  and  K.  B 
strike  the  ends  and  sides  of  oval. 


386 
AN  ORNAMENTAL  PAPER   HOLDER. 

Tinners  with  leisure  who  desire  to  use  their  handiwork  in 
making  something  for  Christmas,  will  be  interested  in  the 


accompanying  illustration  which  we  reproduce  from  a 
European  journal.  It  is  intended  for  a  holder  for  paper, 
magazines,  or  sheet  music. 

HEATING  AND  VENTILATION. 

Much  continues  to  be  said  and  written  about  heating  and 
ventilation,  and  some  may  consider  it  a  worn-out  subject ;  but 
so  long, as  millions  of  people  continue  to  be  poisoned  by 
impure  air,  agitation  to  secure  reform  cannot  be  overdone. 
It  will  dd':no  harm,  therefore,  to  again  name  some  of  the  evi- 
dences and  consequences  of  a  lack  of  ventilation:  Head- 
ache; dull  pressure  on  the  lungs  ;  lungs  become  parched,  pro- 
ducing irritation  ;  dfyness  of  the  throat,  producing  sore 
throat ;  a  feverish  condition  of  the  whole  system.  These  are 
some  of  the  immediate  consequences,  but  by  no  means  embrace 


3*7 

all  the   ultimate   evil  effects.      It   shou'd   be  the  duty  of  all 
fnrnacemen  to  call  the  attention   of  their  patrons  to  these 

c  c 


7 


Fig  I 


matters.  Furnaces  are  often  blamed  for  the  quality  of  air 
supplied,  while  the  fault  lies  solely  with  the  operators  in  not 
making  provision  for  the  supply  of  pure  air  to  the  furnace, 
and  proper  ventilation. 

This  subject  will  not  take  care  of  itself.  We  must  first 
feel  lhat  fresh  air  is  worth  taking  some  trouble  to  obtain,  and 
then  we  must  study  ho\v  to  obtain  it  without  the  body's 
becoming  either  chilled  or  overheated  in  summer  or  winter, 
in  the  daytime  or  in  the  night.  At  night  more  care  needs  to 
be  taken  to  secure  ventilation,  because  there  are  no  doors 
being  opened ;  no  stirring  about  to  promote  circulation. 
Especially  should  pure  air  be  supplied  to  the  sick  room,  and 
the  vitiated  air  removed. 

In  summer  we  depend  on  the  natural  movement  of  the  air 
for  ventilation,  windows  and  doors  being  open  more  or  less. 
In  winter,  with  the  house  closed  up,  it  requires  thought  and 
effort  to  provide  fur  a  change  of  air  in  apartments.  It  must 
be  remembered  that,  under  natural  conditions,  air  moves  hor- 
izontally, according  to  the  direction  of  the  wind.  Heat  causes 
air  to  move  in  a  perpendicular  direction.  In  dry  weather, 
heated  air  andsmoke  will  rise  until  the  same  density  of  atmos- 
phere is  reached,  which  soon  results  from  loss  of  heat.  When 
the  at  mo  phere  contains  a  great  deal  of  moisture,  s.noke  will 
descend,  on  account  of  quick  condensation  and  loss  of  heat. 

This  principle,  understood  by  all  must  be  kept  in  view  in. 
any  plan  for  ventilation.  Suppose  we  wish  to  ventilate  a 
room  in  the  morning  when  the  air  outside  has  become  a  little 
warmer  than  the  air  inside.  The  upper  part  of  a  window 
being  opened  the  warmer  air  outside  would  blow  across  the 
lop  of  the  room,  leaving  the  air  below  undisturbed  Now, 
if  we  open  the  window  at  the  bottom  we  shnll  secure  a  cii> 
Culation  of  air  in  the  room.  While  the  outside  air  is  warmer 
we  do  not  notice  the  draft.  Suppose  we  now  go 'Lito  the 
kitchen,  where  the  windows  are  only  opened  at  the  bottom 
and  raised  halfway  up;  we  shall  feel  the  lower  part  is  cool, 


while  the  i.ir  in  the  upper  part  is  undisturbed.  ]\o,v,  if  we 
open  the  top  of  the  window  and  divide  the  difference  so  as  to 
have  the  top  and  oottom  open,  we  shall  have  a  circulation. 
Or  if  we  open  a  door  and  hold  a  candle  at  the  top  and  then 
at  the  bottom,  we  will  see  the  same  circulation  illustrated  by 
the  cold  air  flowing  in  at  the  bottom  and  the  hot  air  out  at 
the  top.  These  experiments  furnish  the  natural  laws  which 
should  govern  ventilation. 

Carbonic  acid  gas  from  respiration  and  other,  exhalations 
of  the  body,  as  well  as  gases  caused  by  decayed  vegetation  in 
cellars,  or  from  garbage,  sewer  emanations  or  any  kind  of 


filth  are  all  poisonous,  and,  being  heavier  than  pure  air,  sink 
to  the  bottom  of  a  room  by  gravitation.  It  is  a  gross  error 
to  suppose,  as  many  do,  that  the  foul  air  rises  to  the  ceiling 
and  remains  there.  The  sickness  and  death  of  children,  often 
attributed  to  other  causes,  arises  from  blood-poisoning  from 
the  foul  air  near  the  floor  to  which  children  are  much  more 
exposed  than  grown  persons. 

The  illustrations  given  herewith  will  show  where 
the  foul  air  is  and  how  it  is  confined  unless  drawn 
off  by  some  superior  force.  In  Fig.  i,  A  represents  a 
cellar,  DD  the  walls,  CC  the  surface  of  the  ground  outside  of 
the  house.  Foul  air  seeks  the  lowest  space  by  gravitation, 
therefore  all  below  CC  is  foul  air  because  there  is  no  ventila- 
tion to  draw  it  away.  So  long  as  it  remains  stagnant,  pure 
air  will  not  take  the  place  of  the  foul.  JVow,  if  we  place  a 
furnace  in  the  cellar,  as  shown  in  Fig.  2,  and  take  the  air 
from  the  same,  it  would  amount  to  almost  the  same  thing  as 
living  in  the  cellar,  for  you  breathe  the  same  air.  Opening 
the  windows  furnishes  an  outlet  for  the  warm  air  and  thus 
Cools  off  the  furnace;  but  the  same  foul  air,  dust  and  ashes 
are  brought  up  from  the  furnace  for  inhalation. 

Again,  if  the  rooms  are  closed,  the  air  from  the  furnace 
v  ill  rise  to  the  ceiling,  then  pass  to  the  windows,  where  the 


temperature  will  be  reduced,  and  will  then  descen  I  to  the 
floor  and  down  the  sides  of  the  hot-air  flue  to  the  furnace  to 
be  reheated  and  sent  up  again.  This  has  been  proven  by  ex- 
periment. The  children  will  be  the  first  to  be  affected  by 
this  reheated  foul  air. 

How  can  we  obtain  pure  air?  By  ventilation.  How  can 
ventilation  be  secured?  In  various  ways.  The  principal 
method  used  is  the  ventilating  shaft.  One  shaft  is  generally 
sufficient  for  one  dwelling,  and  is  usually  in  the  firm  of  a 
large  chimney,  as  shown  in  Fig.  3.  A  is  the  chimney;  B  is 
a  heavy  sheet-iron  pipe,  with  air  space  around  the  pipe  for 
ventilation;  C is  an  opening  into  tne  pipe  B  for  connection 
with  the  furnace;  Z>is  a  place  for  cleaning  out  just  below  the 
furnace  opening;  these  two  openings  should  be  in  the  cellar 
where  the  furnace  is;  C  is  the  place  for  the  kitchen  stove, 
which  will  supply  sufficient  heat  for  ventilating  the  house  dur- 
ing the  summer  season.  Fig.  3. 

We  will  next  consider  how  to  supply  the 
furnace  with  pure  air.  It  should  be  taken 
from  the  side  from  which  come  the  pre- 
vailing winds.  Of  course,  care  should  be 
taken  that  it  is  not  polluted  by  a  sewage 
hopper,  water  closet  or  other  source  of  con- 
taination.  The  opening  into  the  air-duct 
should  be  two  feet  or  more  above  the  ground, 
and  should  be  covered  with  fine  wiie  gauze. 
The  air-duct  should  be  carried  along  the 
ceiling  of  the  cellar  until  it  reaches  the  fur- 
nace, as  shown  by  dotted  lines  in  Fig.  2, 
then  drop  down  at  the  side  of  the  furnace  to 
the  bottom.  The  space  around  the  furnace 
should  be  made  air-tight.  Any  foul  air  in 
the  cellar  will  be  drawn  into  the  fire-box  of 
the  furnace  to  promote  the  combustion  of 
the  fuel.  The  area  of  the  cold-air  duct 
should,  in  no  case,  be  less  than  half  the  area 
of  the  hot-air  pipes. 

In  setting  a  furnace,  particular  carej 
snould  be  taken  to  see  that  the  chimney  has 
a  good  draught.  There  should  be  sufficient  height  between 
the  top  of  the  furnace  and  the  ceiling  of  the  eel  ar  to  permit 
a  good  rise  for  all  the  hot-air  pipes  from  the  furnace. 
If  there  is  not  sufficient  height  in  the  collar  to  admit 
of  this,  the  furnace  should  be  set  into  a  ^it  dug  out 
below  the  cellar  floor  and  bricked  up.  Ample  room 
should  be  allowed  in  front  ,of  the  furnace  for  cleaning 


out  ashes.  All  the  pipes  should  be  kept  as  close  to  the 
furnace  as  possible.  If  any  hot-air  pipe  is  extended  more 
than  fifteen  feet  from  it,  it  should  be  encased  with  about 
half  an  inch  space  around,  with  both  ends  of  casing  entirely 
closed,  to  prevent  the  loss  of  heat.  The  location  of  the 
furnace  should  be  so  that  the  length  of  hot-air  pipes  shall  be 
about  equal.  The  smoke-pipe  should  be  run  directly  to  the 
chimney.  Dampers  should  be  placed  ia  all  the  hot-air  pipes 
close  to  the  furnace,  and.  when  the  pipes  are  not  in  use,  the 
dampers  should  be  closed.  The  vapor-pan  should  be  placed 
where  the  water  will  not  boil.  In  some  cases,  if  set  on  the 
top  of  the  furnace,  the  water  will  boil  over  aii,l  crack  the 
furnace.  A  proper  place  must  be  provided  for  it.  In  a  brick- 
set  furnace,  the  vapor-pan  should  be  automatic  in  action, 
being  connected  with  an  outside  pan  with  a  ball  and  cock. 
Without  this  arrangement  it  is  hard  to  keep  up  a  regular 
supply  of  vapor,  as  this  is  a  point  generally  neglected. 

In  order  to  distribute  the  heat  through  the  rooms,  the 
ventilating  registers  must  be  located  in  the  proper  places. 
They  should  be  placed  in  the  floor  near  the  windows  or  in  the 
coldest  part  of  each  room,  so  as  to  draw  the  heat  to  tliat 
part.  Never  run  a  hot-air  pipe  up  an  outside  wall  if  you 
wish  success  with  your  work.  If  ventilators  are  put  into  a 
side  wall,  be  sure  that  they  extend  down  entirely  to  the  floor, 
otherwise  there  will  be  a  cold  stratum  of  air  next  the  floor, 
causing  cold  feet.  A  failure  to  do  this,  causes  children  to 
have  cold  feet  at  school.  People  frequently  suffer  in  a  simi- 
lar way  at  church. 

TWO  SPINDLE  MILLING  MACHINE. 

The  illustration  represents  a  milling  machine  of  new  de- 
sign, recently  built  by  E.  W.  Bliss  Company,  of  Brooklyn, 
N.  Y.,  for  use  in  their  own  works. 

As  will  be  seen,  the  general  arrangement  is  that  of  a  planer, 
but,  in  the  place  of  the  ordinary  planer  tools,  are  substituted 
vertical  spindles  for  butt  milling. 

The  table  has  a  longitudinal  travel  of  36  inches,  and  is  fed 
by  a  screw  which  may  be  operated  by  the  hand-wheel  shown 
at  right  side  of  bed,  or  fed  by  power,  in  either  direction. 

Four  speeds  for  feed  for  the  table  are  provided,  and  in 
addition  a  power  '-rapid  transit"  motion,  which  is  operated 
to  run  the  table  in  either  direction,  by  means  of  the  hand-iever 
shown  to  the  right  of  bed.  The  quick  motion  is  especially  in- 
tended for  running  the  table  back  alter  the  cut  is  finished,  and 
being  entirely  independent  of  the  cone  feed,  both  can  be  In 


391 

operation  atone  and  the  same  time,  thus  saving  the  trouble 
of  throwing  off  the  cone-feed  in  order  to  run  the  table  back 
for  starting  a  new  cut. 

The  cross-head  is  raised  and  lowered  by  power,  much  in 
the  same  manner  as  in  a  planer,  and  in  addition  ea<  h  spindle 
has  an  independent  vertical  adjustment  of  two  inches  oper- 
ated by  the  hand  cranks  shown  at  the  upper  boxes  on  saddles. 
Each  saddle  is  capable  of  independent  lateral  motion,,  oper- 
ated by  the  large  hand-wheel  at  front,  and  has  also  a  p  >wcr 
attachment  for  feeding,  supplied  with  four  changes  of  speed. 

As  in  the  case  of"  the  table,  the  saddles  nay  be  moved 
independently  from  the  power  feed  while  the  latter  is  in  oper- 
tion.  The  cross-head  is  made  of  sufficient  lengtli  to  allow 
the  saddles  to  be  run  out  far  enough  to  bring  the  nulling  cut- 
ters outside  of  the  housings,  between  which  the  distance  is 
fifty-four  inches. 

The  machine  illustrated  was  built  for  special  v\ork  not 
requiring  a  long  table,  but  the  latter  can  be  made  of  any 
length  required,  and  the  builders  are  now  filling  several  orders 
for  machines  with  five  to  six  feet  length  of  table. 

The  driving-shaft,  carr'ed  by  cross-head,  is  splined  its 
length  between  bearings  to  allow  for  the  lateral  motion  of  the 
saddles,  and  is  driven  from  the  floor  counter  by  the  familiar 
arrangement  of  belting  shown,  which  dispenses  with  the 
necessity  of  a  tightener  to  make  up  for  the  -vertical  arljirrt- 
ment  of  the  cross-head. 

In  some  of  the  machines  now  in  corpse  of  construction, 
the  arrangement  is  such  as  to  allow  the  floor  counter  to  be 
dispensed  w?ith,  and  one  at  top  of  machine  to  be  substituted, 
which,  in  some  cases,  might  be  considered  preferable. 

By  the  use  of  the  two  spindles  on  the  work  for  which  this 
machine  was  designed,  and  with  special  attachments  to  facili- 
tate the  setting,  this  tool  is  now  doing  work  that  heretofore 
required  the  use  of  five  planers,  thus  proving  itself  a  most  val- 
uable addition  to  the  equipment  of  a  machine  shop. 

EXPLOSION  OF  A  DOMESTIC  HOT  WATER 
BOILER. 

Explosions  of  domestic  hot  water  boilers  attached  to 
cooking  ranges,  water-backs  in  ranges,  etc.,  through  freezing 
up  of  the  pipes  in  cold  weather,  are  becoming  so  frequent 
that  it  may  not  be  out  of  place  to  give  an  account  of  one  o* 
the  most  destructive  ones  that  has  occurred  recently,  and 
point  out  its  cause. 

The  boiler  in  question  was  used  in  an  hotel  in  a  large  city 


392 

in  one  of  the  Northwestern  States,  where  the  temperature  is 
very  low  at  times.  It  was  connected  to  the  kitchen  range, 
the  range  was  a  very  large  one,  and  the  heating  surface  was 
furnished  by  a  coil  of  j^  inch  pipe,  placed  near  the  top, 
instead  of  the  cast-iron  front  or  back,  such  as  is  commonly 
used  in  the  smaller  ranges  in  private  dwellings.  The  con- 
nections to  the  boiler  were  made  in  the  usual  manner ;  the 
accompanying  cut  shows  its  essential  features. 

The  operation  of  all  boilers  of  this  sort  is  as  follows : 
The  connections  being  made,  as  shown  in  cut,  the  water 
is  turned  on  from  the  main  supply,  and  the  entire  system  is 


RANGE 


fil.  d  with  water.  When  it  is  filled,  and  all  outlets  are 
closed,  it  is" evident  that  no  more  water  can  run  in,  although 
the  boiler  is  in  free  connection  with,  and  is  subjected  to,  the 
full  pressure  of  the  source  of  supply.  When  a  fire  is  started 
in  the  range,  and  the  water  in  the  circulating  pipes,  or 
water-back,  is  heated,  the  water  expands,  is  consequently 
lighter,  and  flows  out  through  the  pipe  into  the  boiler  at  A, 
as  this  connection  is  placed  higher  up  than  the  one  at  B  ; 
this  starts  the  circulation,  and  the  water,  as  it  becomes 


393 

heated,  constantly  flows  into  the  boiler  at  A,  and  rises  to  the 
upper  part  of  the  boiler,  while  the  cooler  water  at  the  bot- 
tom of  the  boiler  flows  out  into  the  circulating  pipes  at  B, 
and,  if  no  water  is  drawn,  a  slow  circulation  goes  on,  as  heat 
is  radiated  from  the  boiler,  in  the  direction  indicated  by  the 
arrows,  the  water  at  the  top  of  the  boiler  always  being  much 
hotter  than  at  the  bottom.  WLien  the  hot  cock  is  opened, 
cold  water  instantly  begins  to  flow  into  the  boiler  at  D,  by 
reason  of  the  pressure  on  the  city  main,  and  forces  hot  water 
out  of  the  boiler  at  C.  Thus  it  will  be  seen  that  hot  water 
cannot  be  drawn  unless  the  cold  water  inlet  is  free,  and  it  is 
equally  evident  that  cold  water  cannot  enter  the  boiler  unless 
the  hot  water  cock  or  some  other  outlet  is  open. 

The  above  points  being  understood,  we  are  in  a  position 
to  investigate  the  cause  of  the  explosion  referred  to,  which 
killed  one  person  and  badly  injured  twelve  or  thirteen  others, 
besides  badly  damaging  the  building. 

On  the  morning  of  the  explosion  fire  was  started  as  usual 
in  the  range  about  four  o'clock  a.  m-  It  was  found,  on  try- 
ing to  draw  water,  that  none  could  be  had  from  either  cold 
or  hot  water  pipes:  it  was  rightly  judged  that  the  j>ipes  were 
frozen.  The  fire  was  continued  in  the  range,  however,  and 
the  breakfast  prepared  as  best  it  could  be,  and  a  plumber  sent 
for  to  thaw  out  the  pipes.  He  arrived  on  the  premises  about 
seven  o'clock,  as  would  naturally  be  the  case.  He  opened 
both  hot  and  cold  water  cocks,  and,  getting  neither  steam  nor 
water,  concluded  there  was  no  danger,  and  proceeded  to 
thaw  out  some  pipes  in  the  laundry  department  first.  About 
an  hour  afterward  the  explosion  occurred.  The  lower  head 
of  the  boiler  let  go,  and  the  main  portion  of  the  boiler  shot 
upward  like  a  rocket  through  the  four  stories  of  the  hotel 
and  out  through  the  roof. 

The  coroner  held  an  inquest  on  the  remains  of  the  person 
killed,  and  some  of  the  testimony  given,  as  reported  in  a 
local  paper,  would  be  amusing  were  it  not  for  the  tragic 
nature  of  the  affair  which  called  it  out.  The  usual  expert, 
with  the  usual  vast  and  unlimited  years  of  experience,  was 
there,  and  swore  positively  to  statements  which  a  ten-year- 
old  boy  who  had  been  a  week  in  the  business  ought  to  be 
ashamed  to  make.  He  had  examinee!  the  wreck  with  a  view 
to  solving  the  mystery  (?)  The  matter  was  as  much  of  a 
mystery  now  as  oh  the  day  of  the  explosion.  His  theories 
were  exploded  as  fast  as  he  presented  them.  The  boiler  must 
have  been  empty.  If  it  had  been  full  of  water,  it  could  not 
possibly  have  exploded,  etc.,  etc.  And  then  a  lot  more 
nonsense  about  the  "peculiar"  construction  of  the  boiler. 


394 

As  a  matter  of  fact,  there  was  nothing  peculiar  about  the 
boiler  or  its  connections.  Everything  was  precisely  like  all 
boilers  of  its  class,  of  which  there  are  probably  hundreds  of 
thousands  in  daily  operation  throughout  the  country,  and, 
moreover,  they  were  all  right. 

Now  let  us  inquire  what  caused  the  explosion.  Every- 
thing was  all  right  at  eight  o'clock  the  previous  evening,  for 
water  was  drawn  at  that  time.  The  fire  was  built  in  the 
range  at  four  o'clock  a.  m.  It  is  admitted  that  the  cold 
water  supply  pipes  were  frozen,  for  no  water  could  be  had 
for  kitchen  use.  It  is  also  proved  absolutely  that  the  hot 
water  supply  was  frozen  or  otherwise  stopped  up,  by  the  fact 
that  at  seven  o'clock  the  plumber  who  came  to  thaw  out  the 
pipes  opened  the  hot  water  cock  and  got  "neither  water  nor 
steam."  Here  was  his  opportunity  to  prevent  any  trouble, 
but  he  let  it  pass.  Any  one  who  understood  his  business 
would  have  known  that  there  must  have  been  a  tremendous 
pressure  in  the  boiler  at  this  time,  as  the  range  had  been  fired 
steadily  for  three  hours;  there  were  about  eight  square  feet 
heating  surface  exposed  to  tne  fire  by  the  circulating  pipe  in 
the  range,  and  there  had  been  no  outlet  for  the  great  pressure 
which  must  have  been  generated  during  this  three  hours 
firing.  The  blow-off  cock  should  have  been  tried  at  once; 
if  this  were  clear,  and  tha  probability  is,  from  its  proximity 
to  the  range,  that  it  was  clear,  the  pressure  could  have  been 
relieved,  and  disaster  averted.  If  the  blow-off  proved  to  be 
stopped  up,  then  the  fire  should  have  been  at  once  taken  out 
of  the  range.  At  the  time  the  plumber  opened  the  cocks 
connecting  with  the  boiler,  it  probably  was  under  a  pressure 
of  400  or  500  pounds  per  square  inch.  An  ordinary  cast- 
iron  waterback  such  as  is  used  in  small  ranges  in  private 
houses  would  have  exploded  shortly  after  the  fire  was  built, 
but  it  will  be  noticed  that  the  heating  surface  in  this  case 
was  furnished  by  a  coil  of  1*4 -inch  "pipe;  this  was  very 
strong,  and  the  boiler  was  the  first  thing  to  give  way,  simply 
because  it  was  the  weakest  part  of  the  system. 

Accidents  of  this  sort  can  be  easily  avoided  by  exercising 
a  little  intelligence  and  care.  The  hot  water  cock  should 
always  be  opened  the  first  thing  on  entering  the  kitchen 
every  morning.  If  the  water  flows  freely,  fire  may  then  be 
started  in  the  range  without  danger-  If  it  does  not  flow 
freely,  don't  build  a  fire  until  it  does.* 

*  A  CEMENT  TO  MAKE  JOINTS  FOB  GRANITE  MONUMENTS— 
Use  clean  sand,  twenty  parts;  litharge,  two  parts;  quicklime, 
one  part,  and  linseed  oil  to  form  a  thin  paste. 


USEFUL  SHOP  KINKS. 


jles,  or  rise  of  elevations 

The  usual  rise  given  to 
furnace  pipe  elbows  is 
one  inch  to  the  foot.  A 
rule  to  obtain  the  desired 
result  is  as  follows,  and 
is  almost  identical  with 
the  one  commonly  used 
to  get  the  height  and 
pitch  of  miter  line  of 
riglit-anglod  elbows.  It 
i >  applicable  to  any  sized 
tliroat  and  any  sized  el- 
b.rvv;  also,  to  elbows 
wit,h  any  number  of 
pieces  or  sections. 

First  draw  lines  a  c 
and  c  6,  Fig.  1,  at  right 
angles  to  each  other. 
From  point  c  on  line  c  ft, 
measure  off  1  foot,  and 
perpendicular  from  the 
point  thus  obtained  erect 
line  d  to  r,  which  is  the 
desired  height  you  wish  the  elbow  to  rise,  or  angle  from  a 
true  right-angled  elbow,  in  this  case  one  inch  to  the  foot. 
From  point  c  as  center,  draw  the  arc  a  to  r.  From  point  r 
draw  the  line  r  c  for  base  line.  This  will  give  the  correct 
elevation,  as  proof  clearly  shows  by  the  dotted  lines  c  to  z 
and  r  to  m;  these  show  the  continuation  that  the  elbow  leads 
to,  namely,  as  in  this  instance,  1  inch  to  the  foot,  or  1  foot 
in  12  feet.  The  line  c  to  x  is  1  foot,  and  from  x  to  z,  1  inch. 

If  an  elbow  of  four  pieces  is  desired,  divide  the  arc  or 
curve  r  to  a  into  six  equal  parts;  if  an  elbow  of  three  pieces 
or  sections  is  wanted,  divide  same  into  four  equal  parts. 
From  point  c  for  a  four-piece  elbow,  draw  line  c  to  *,  and 
from  point  n,  where  inner  curve  of  elbow  intersects  line  c  s, 
draw  line  n  to  I  parallel  to  line  c  r,  and  same  intersecting 
line  r  s  at  I.  This  much  gives  the  pitch  and  rise  for  miter 
line  for  a  four-piece  elbow  of  the  desired  elevation.  For  a 
three-piece  elbow  the  dotted  lines  from  point  k  on  the  inner 


890 


FIG.  3. 


curve  to  points  u  and  o  on  outer  curve,  give  the  miter  de- 
sired. 

I  have  also  shown  a 
smaller-sized  elbow  in 
the  drawing  to  show  how 
the  rule  works,  and  is 
applied  on  same.  It*i  , 
of  course,  not  necessary 
to  give  the  same  size  <.f 
throat,  as  is  given  in  the 
drawing,  nor  the  same 
outside  sweep.  This  rule 
will  suit  a::y  case  or  sized 
elbow  as  m:iy  be  desire  1. 
and  as  one  becomes  f:i- 
miliar  with  the  workiry 
of  the  rule,  some  of  the 
other  lines  need  not  be 
drawn  out,  but  are  hero 
given  to  make  the  draw- 
ing complete. 

The  above  is  given  to 
get  the  complete  data  for 
side  elevation  which  are 
necessary  to  develop  the  • 

patterns  for  the  different 

sections  of  an  elbow.  To  develop  the  same  I  will  give  a 
quick  snap  rule,  which  comes  so  near  right  as  to  be  prac- 
tically almost  correct.  I  will,  however,  first  give  a  good 
snap  rule  for  angles. 

If  Fig.  3  is  examined,  it  shows  the  usual  long  and  tedious 
geometrical  method  of  obtaining  miter  lines  for  both  a  two- 
piece,  and  also  a  three-piece  angle,  both  of  the  angles  being 
of  the  same  pitch.  The  solid  lines  are  for  a  three-piece  angle, 
and  the  dotted  lines  are  for  a  two-piece  angle. 

Now,  to  do  away  with  all  this  drawing,  and  to  get  a  quick 
and  very  nearly  correct  method  to  obtain  the  desired  result, 
suppose  an  angle  is  wanted  as  is  given  by  the  lines  a  b  and 
a  to  c,  Fig.  3,  the  diameter  to  be  as  full  drawing  requires, 
proceed  as  follows:  First  measure  off  the  distance  which  is 
the  size  of  diameter  wanted,  from  a  to  b;  do  the  same  from 
a  to  c,  and  from  points  thus  obtained,  which  are  c  and  6, 
draw  the  line  d  from  c  to  b.  Then  from  either  line,  a  c  or 
line  a  6,  draw  at  right  angles  the  line  a  to  a?,  as  shown,  the 
line  a  x  intersecting  line  d  at  x.  This  much  gives  the  re- 
quired  elevation  for  miter  line  of  a  two-piece  angle  as  called 


397 

for;  line  </from  c  to  x  is  miter  line,  a  to  x  is  height  of  rise, 
and  a  to  r,  base  line,  which  is  size  of  diameter  called  for. 
The  line  x  to  a  divided  into  half  gives  the  point  r  where  the 
miter  line  intersects.,  of  a  three-piece  angle  ;  r  to  a  is  height, 
a  to  c  is  base  line,  and  c  to  r  is  miter  line,  as  will  be  seen  by 
dotted  line  in  drawing.  Twice  the  length  of  distance  of  line 
from  points  a  to  is  the  width  of  outer  curve  of  center  sec- 
tion. You  must,  ot  course,  allow  for  laps  or  burrs  for  join- 
ing same  together  when  cutting  pattern. 

Compare  this  with  the  solid  line  center  section  of  full  side 
elevation,  and  see  how  much  quicker  this  method  is  over  the 
old  way.  When  once  accustomed  to  use  this  method,  you 
will  use  no  other.  This  rule  is  absolutely  correct  for  a  two 
piece  angle,  and  varies  so  little  on  a  three-piece  angle  from. 


'rig.  a 


being  absolutely  correct,  as  that  the  variation  is  practically 
of  no  moment. 

To  develop  the  stretch-out,  Fig.  2,  lay  out  the  full  length 
of  circumference,  as  is  shown  in  Fig.  2  from  a  to  b,  and 
divide  this  length  into  six  equal  parts  as  in  drawing.  Make 
the  center  line,  No.  2,  same  height  as  required,  as  in  this 
case  for  the  two-piece  angle  of  Fig.  3.  Next  divide  the 
right  and  left  lines  nearest  to  the  center  line,  into  four  equal 
parts,  and  mark  of  one  off  these  parts  nearest  to  the  top  of 
each  line ;  and  do  the  same  as  to  s  ^acing  to  the  lines  nearest 
to  the  end  of  stretch-out,  as  lines  No.  4  and  r,  but  with  the 
difference  that  you  mark  off  one  space  at  the  bottom  of  each 
Kne  as  the  drawing  fully  shows.  Continue  the  center  line 


39s 

indefinitely  downward,  and  with  dividers  strike  the  arc  i,  2 
and  3,  cutting  lines  at  points  i,  2  and  3.  Draw  line  b  in- 
definitely upward,  reverse  the  dividers,  and  with  line  b  as 
center  In",  draw  the  arc  from  point  5  to  point  4,  cutting 
points  5  a.id4;  d;>  the  sa.ne  on  the  other  end.  Then  draw  a 
Straight  line  from  paint  3  to  4,  and  same  from  i  tor.  This 
completes  the  pattern.  Allow  for  locks  or  laps  on  both 
ends,  and  miter  line^,  of  course. 

The  met  ho  1  given  above  is  an  old  one,  but  not  so  uni- 
versally  1-  no\\ii  a  nong  tinners  as  its  merits  deserve.  This 
method  is  also  applicable  to  develop  the  pattern  for  elbow 
as  given  in  Fig.  i.  I  use  it  for  all  kinds  of  elbows. 

TO  DRAW  ANY  OVAL  WITH  SQUARE  AISTI> 
CIRCLE. 


The  following  is  a  correct  rule  to  draw  any  size  or  ova! 
tised  in  the  tin  shop,  with  square  and  circle  : 

Draw  the  line  from  I  to  2,  which  is  the  length  of  the.ovai 
Draw  line  from  center  to  3,  which  is  one-half  the  width,  and 
draw  a  line  from  i  103.  Set  compass  from  i  to  center  ; 
leave  one  point  on  i,  and  mark  4.  Set  compass  from  center 
103.  Leave  one  end  (of  compass)  in  center  ami  mark  5.  Set 
compass  from  4  to  5.  and  from  6  draw  head  lines  of  circles  7 
and  8,  and  clut  7  and  8  from  points  i  and  2.  Set  compass 
from  7  to  7,  and  mark  9  from  7  7  and  8  8.  Complete  oval 
from  9. 


399 
RAIN  WATER  STRAINER. 

I  hand  you  a  sketch  of  a  rain  water  strainer  which  I  have 
put  up  and  which  gives  good  results.  It  is  eighteen 
inches  high,  twelve  inches  in  diameter  at  the  half-circle,  five 
and  a  half  inches  length  of  bottom,  and  five  inches  deep. 
Allow  for  all  seams. 

At   A'2,  D>  B2y  B>  represents    the   outside  of  finished 


strainer.  K "ts  a,  section  of  circular  top  hinged  at  B*  and 
fastened  with  a  turn  button.  The  dotted  lines  at  E  show 
the  section  of  circular  top,  A*,  partly  open;  m  is  a  galvanized 
strainer  with  three-eighth  inch  holes.  The  strainer  rests 
upon  supports  at  the  ends,  and  may  be  removed  at  will.  /. 
is  a  tin  strainer  with  one-eighth  inch  holes,  and  is  soldered  in 
place.  F  and  G  are  three-inch  inlet  and  outlet.  2  2  are 
straps  on  back  side,  by  which  the  strainer  is  fastened  to  ths 
building. 

As  will  be  seen,  the  top  strainer  catches  the  refuse  whic5i 
is  washed  from  the  roof  and  gutters,  and  is  easily  taken  out; 
the  finer  particles  ate  <•  t^ht  below  ap-l  irt1. -l»e  removed 
when  the  top  strainer  is  out. 


400 

OVAL    DAMPER. 

Inclosed  please  find  method  of  obtaining  an  oval  damper,* 
tliat  when  closed  in,  the  pipe  will  be  at  an  angle  of  45°. 

Let    A    B    C    D 


lepre 

sent  the  pipe,  and  E  F 
the  line  through  the  pipe  at 
an  angle  of  45°,  which  will 
be  the  position  of  the  damper 
when  closed.  Divide  the 
semi-circle  into  any  even  num- 
ber of  equal  parts,  as,  I,  2,  3, 
4,  etc.  (even  numbers,  because 
in  doing  so  you  obtain  the 
center  line  of  the  short  diam- 
eter of  the  damper).  Carry 
lines  up  until  they  cut  the 
line  E  F  as  dotted  lines,  then 
draw  solid  lines  across,  and 
at  right  angles  to  the  line 
E  F,  and  number  them  to 
correspond  with  spaces  in 
semi-circle,  as  I,  2,  3,  4,  etc. 
With  the  dividers  step  from 
a  to  i  on  dotted  line,  and 
with  one  point  of  the  dividers 
at  a';  cut  the  solid  line  I  each 
side  of  the  line  E.  F.  Step 
from  b  to  2,  and  with  one 


it 


j  ytf 


point  of  the  dividers  on  b',  cut  the  solid  line  to  both  sides  of 
the  line  E  F,  and  so  on  until  all  the  spaces  have  been  trans- 
ferred. Now  set  the  dividers  so  as  to  draw  an  arc  through 
the  points  5,  6,  7,  both  sides  of  the  line  E  F,  and  then  set 
them  to  draw  the  two  end  circles,  as  n,  12,  n,  and  1,0,  I. 
Draw  a'  line  free  hand  through  the  points  from  i  to  ,5,  and 
from  7  to  n,  both  sides  of  line  E  F,  and  you  have  the  re- 
quired damper. 

The  same  method  is  used  to  obtain  the  shape  of  a  hole  in 
piece  of  sheet  metal  that  a  pipe  is  to  pass  through  on  an 
angle.  For  instance,  let  A  B  C  D  represent  a  pipe,  and 
E  F  a  roof  through  which  the  pipe  passes ;  we  want  a  piece 
of  iron  or  tin  laid  on  the  roof  for  the  pipe  to  pass  through ; 
we  want  to  know  how  to  get  the  shape  of  the  opening. 
Employ  this  m"thud  and  it  will  give  you  the  required  article 


A  TAPERING  ROUND-CORNERED  SQUARE 
RESERVOIR. 

'Not  long  since,  there  was  an  inquiry  in  your  columns  for 
a  pattern  for  a  tapering,  round-cornered  square  reservoir.  1 
give  herewith  diagrams  for  constructing  such  a  pattern  : 

Fig.  i  is  the  size,  top  and  bottom  (A  C  F  H  D  B  G  E  is 
the  top,  and  I.K  NP  LJOMis  the  bottom),  and  Fig.  I 
the  upright  height.  Take  the 
perpendicular  height  ad,  Fig 
I,  and  mark  it  off  from  h  to  k, 
Fig.  3.  Take  the  radius  for 
the  corners  d  C,  Fig.  I,  and 
mark  it  off  from  h  to  i,  Fig. 
3,  also  the  radius  dK;  mark 
off  from  K  to  1,  drawing  ;».  line 
from  il  to  cut  the  line  li  K, 
which  gives  the  slanting  height 
and  the  radius  required  for 
striking  the  corners.  Draw  the 
lines  I  1C  and  AC,  Fig.  4,  the 
same  length  as  I  K,  Fig.  2,  am1 
the  same  distance  apart  as  1  to  i, 
Fig.  3  ;  prolong  the  lines  A  I 
and  C  K,  Fig.  4,  till  Ac  and 
C  d  equals  to  i  m,  Fig.  3. 
With  radius  d  C,  Fig.  4,  using 
d  and  c  as  centers,  strike  the 
curves  C  F  and  A  F,  and,  with 
a  radius  d  K,  Fig.  4,  using  the  same  centers,  strike  the 
curves  K  N  and  I  M.  Take  the  length  of  the  large  quar- 

Fig.  3- 


ter-circle  1)   H,  Fig.  2,  and  dot  off  the  same  distance  from 
C  to  F,  Fig.    4;    make    A    R  e^jual    to    C  F.   and    draw 


4O2 

lines  from  E  and  F  to  the  ceniers  c  and  d;  draw  EG 
and  M  O  at  right  angles  with  E  c.  Take  the  dis- 
tance from  A  to  C,  and  make  the  same  distance  from 
E  to  G  and  M  to  O,  Fig.  3.  DrawGe  parallel  to  EC. 
From  G  mark  off  point  e,  the  same  length  as  E  to  c,  then, 
using  e  as  center,  strike  the  curves  G  B  and  O  J,  making  the 
curve  G  B  equal  to  A  E ;  draw  line  from  B  to  center  c, 
draw  B  T  and  J  R  at  right  angles  to  Be,  taking  the  distance 
from  B  to  S,  Fig.  2,  mark  off  the  same  distance  from  B  to 
S  and  J  to  R,  draw  S  R  parallel  with  <B  e,  and  proceed  in  the 
same  manner  with  the  .other  end;  adding  on  the  laps,  as 
shown,  will  make  the  pattern  complete  in  one  piece,  being 
joined  together  at  R  S. 

PATTERN  FOR  T  JOINTS. 

The  following  rule  is  a  short  and  explicit  method  of  ob- 
taining a  pattern  for  T  joints  where  different  diameters  are 
required.  Suppose,  for  instance,  a  T  is  required  whose  diam- 
eters are  3  and  8  inches  respectively. 

Divide  the  stretch-out,  a  a  (which  must    be    the  exact 

length  required  to  form  up 
3  inches,  allowing  for 
locks  as  shown  by  dotted 
lines)  in  center  as  shown 
in  the  figure.  Then 
divide  each  half  equally 
between  6-7  and  7-8  as 
shown  by  indefinite  lines 
2  and  3.  Now  spread  the 
compass  to  8  inches,  which 
is  the  diameter  of  the 
large  pipe,  set  one  point 
at  4,  and  the  other  at 
6;  strike  a  circle  to  7; 
then  set  compass  on  the 
other  line  at  5  and  draw 
circle  7  to  8.  Cut  out  the  circles,  and  you  have  your  pattern. 
The  same  rule  applies  to  any  diameter  by  spreading  compass 
to  the  larger  diameter  and  striking  the  circle  on  the  stretch- 
out required  for  smaller  diameter  as  shown  above. 

Ireland  has  seventy-six  collieries  —  nine  in  Ulster,  seven 
in  Connaught,  thirty-one  in  Leinster,  and  twenty-nine  in 
Minister.  Very  few  of  these  are  being  worked. 


403 
NOVEL  DRAWING  INSTRUMENT, 


A  pair  of  dividers,  or 
compasses,  which  will  de- 
scribe any  figure  is  shown 
herewith.  It  is  of  Eng- 
lish origin  and  very  simple. 
The  former,  or  template 
A,  is  affixed  to  one  le<:, 
and  beats  against  the  mid- 
leg  B,  around  which,  of 
course,  revolves  the  work- 
ing leg.  By  this  means 
the  drawing  pen  or  pencil 
is  moved  in  and  out  in  an 
obvious  manner.  Speci- 
mens of  the  work  are 
shown  in  Fig.  2. 


The  quality  of  wood  is   determined   by  the   number  of 
spirals.     The  best  has  about  thirty  "  crinkles  "  in  an  inch. 


404 

TO    DESCRIBE   A   PATTERN    FOR   A  TAPERING 
SQUARE  ARTICLE. 

Erect  the  uerpendicular   line   G  E ;   draw  the   line  A  B 

at  right  angle  to 
make  E  K 


G  E ; 

equal  to  the  slant 
height,  and  draw 
the  line  C  D  par- 
allel to  A  B;  make 
AB  equal  in 
length  to  one  side 
of  the  base;  make 
CD  equal  in 
length  to  one  side 
of  the  top  or 
smallest  end,  draw 
the  lines  AGand 
B  G,  cutting  the 
points  A  C  and 
BD,  Gasa  center 

with  the  radii  G  C  and  G  A.     Describe  the  arcs  K  M  and  J  I ; 

set  off  on  the  arc  J  I,  J  A,  B  H  and  H  I  equal  in  length  to  A  B, 

and  draw  the  lines  J  G,  H  G,  and  I  G,  also  the  lines  J  A,  B  H, 

HI,  and  KC,  D  L,  L  M. 
Edges  to  be  allowed. 

THE  PAINTING  OF   IRON. 

Cast  and  wrought  iron  behave  very  differently  under 
atmospheric  influences,  and  require  somewhat  different  treat- 
ment. The  decay  of  iron  becomes  very  marked  in  certain 
situations,  and  weakens  the  metal  in  direct  proportion  to  the 
depth  to  which  it  has  penetrated,  and,  although  where  the 
metal  is  in  a  quantity  this  is  not  appreciable,  it  really  becomes 
so  when  the  metal  is  under  three  fourths  of  an  inch  in  thick- 
ness. The  natural  surface  of  cast  iron  is  very  much  harder 
than  the  interior,  occasioned  by  its  becoming  chilled,  or  by 
its  containing  a  large  quantity  of  silica,  and  affords  an  excel- 
lent natural  protection,  but,  should  this  surface  be  broken, 
rust  attacks  the  metal  and  soon  destroys  it.  It  is  very  desira- 
ble that  the  casting  be  protected  as  soon  after  it  leaves  the 
mold  as  possible,  and  a  priming  coat  of  paint  should  be 
applied  for  this  purpose  :  the  othei  coats  thought  requisite 
can  be  given  at  leisure.  Jn  considering  the  painting  of 
wrought  iron,  it  must  be  noticed  that,  when  iron  is  oxidized 
by  contact  with  the  atmosphere,  two  or  three  distinct  layers 


405 

of  scale  for  1.1  on  the  surface,  which,  unlike  the  skin  upon 
cast  iron,  can  be  readily  detached  by  bending  or  hammering 
the  metal.  It  will  be  seen  that  the  iron  has  a  tendency  to 
rust  from  the  moment  it  leaves  the  hammer  or  rolls,  and  the 
scale  above  described  must  come  away.  One  of  the  plans  to 
preserve  iron  has  been  to  coat  it  with  paint  when  still  hot  at 
the  mill,  and,  although  this  answers  fur  a  while,  it  is  a  very  trou- 
ble^ome  method,  which  iron  masters  cannot  be  persuaded  to 
adopt,  and  the  subsequent  cutting  processes  to  which  it  is 
submitted  leave  many  parts  of  the  iron  bare.  Besides,  a  good 
deal  of  the  scale  remains,  and,  until  this  has  fallen  off  or  been 
removed,  any  painting  over  it  will  be  of  little  value.  The 
only  effectual  way  of  protecting  wrought  iron  is  to  effect  a 
thorough  and  chemical  cleansing  of  the  surface  of  the  metal 
upon  which  the  paint  is  to  be  applied ;  that  is,  it  must  be 
immersed  for  three  or  four  hours  in  water  containing  from 
one  to  two  per  cent,  of  sulphuric  acid.  The  metal  is  after- 
ward rinsed  in  cold  water,  and,  if  necessary,  scoured  with 

.sand,  put  again  into  the  pickle,  and  then  well  rinsed.  If  it 
is  desired  to  keep  iron  a'ready  cleansed  for  a  short  time  before 
painting,  it  is  necessary  to  preserve  it  in  a  bath  rendered  alka- 
line by  caustic  lime,  potash,  soda,  or  their  carbonates.  Treat- 
ment with  caustic  lime  water  is,  however,  the  cheapest  and 
most  easy  method,  and  iron  which  has  remained  in  it  some 
hours  will  not  rust  by  a  slight  exposure  to  dampness.  Hav- 
ing obtained  a  clean  surface,  the  question  arises,  what  paint 
should  be  used  upon  iron  ?  Bituminous  paints,  as  well  as 

.  those  containing  variable  quantities  of  lard,  were  formerly 
considered  solely  available,  but  their  failure  was  made  appar- 
ent when  the  structure  to  which  they  were  applied  happened 
to  be  of  magnitude,  subjected  to  great  inclemency  of  weather 
or  to  constant  vibration.  Recourse  has,  therefore,  been  had 
to  iron  oxide  itself,  and  with  satisfactory  results.  A  pound 
of  iron  oxide  paint,  when  mixed  ready  for  use  in  the  propor- 
tion of  two-thirds  oxide  to  one-third  linseed  oil,  with  careful 
work,  should  cover  twenty-one  square  yards  of  sheet-iron, 
which  is  more  than  is  obtained  with  lead  compound. 

INVENTOR  OF  THE  SCREW-AUGER. 

The  screw-auger  was  invented  by  Thomas  Garrett  about 
IOO  years  ago.  He  lived  near  Oxford,  Chester  County,  Pa^ 
The  single  screw-auger  was  invented  by  a  Philadelphian,  and 
it  is  said  to  be  the  only  one  used  with  any  satisfaction  in  very 
hard  woods,  where  the  double  screw-augers  become  clogged 


RUST  PROOF  WRAPPING  PAPER. 

This  is  made  by  sifting  on  the  sheet  of  pulp,  in  process  of 
manufacture,  a  metallic  zinc  powder  (blue  powder),  about  to 
the  extent  of  the  weight  of  the  dried  paper,  the  pulp  sheet 
is  afterward  pressed  and  dried  by  running  through  the 
rolls  r.nd  over  the  drying  cylinders  as'  usual.  The  zinc  powder 
Hberes  to  the  paper,  and  'is  partly  incorporated  with  it,  the 
amount  varying  with  the  thickness  and  wetness  of  the  pulp 
sheet.  The  paper  may  be  sized  with  glue  or  starch  and  then 
dusted  with  the  zinc  powder,  or  the  powder  mny  be  stirred 
into  the  size  and  then  applied  to  the  surface  of  the  p  per. 
i.f  silver,  brass  or  iron  articles  are  wrapped  in  paper  thus  pre- 
pared, the  affinity  of  the  zinc  for  the  sulphureted  hydrogen 
Always  present  in  the  air),  chlorine  or  acid  vapors,  will  pre- 
vent those  substances  from  attacking  the  articles  inclosed  in  the 
;j;iper. 

IIIP-BATII  IN  TWO  PIECES. 
Fig.  i. 

Draw  the  hip-bath 
full  size,  as  it  would 
look  when  finished, 
as  in  Fig.  i.  Extend 
line  /',  or  the  front,  to 
same  height  as  r,  the 
highest  part  of  the 
tub.  Draw  line  d 
parallel  with  e,  or 
bottom  of  tub,  until 
it  intersects  c  and  b. 
Strike  the  half-circle 
ff9  and  divide  into 
any  number  of  equal 
parts,  as  I,  2,  3,  4, 
etc.  (the  more  lines 
the  better).  For  the 
points  draw  lines  as 
shown  in  profile. 

Set  dividers  same  as 
when  the  circles  in 

Fig.  i  were  described,  and  strike  the  circles  g  g,  and  with  a 
T  square  draw  the  perpendicular  lines//  h  h  h.  Draw  the  line 
/'  parallel  with  the  lines  h.  Take  the  height^  same  as  from  d 
to  e,  in  Fig.  i,  and  mark  the  line  /,  Fig.  :  T)raw  lines  k  k 
until  they  intersect  at  /.  Set  dividers  at  /,  and  strike  the 


407 

circles  m  m.  Draw  line  ;/,  and,  taking  it  as  the  center  Jin*, 
step  each  way  one-fourth  of  the  circumference,  in  as  man? 
parts  as  in  profile,  I,  2,  3,  4,  etc.,  and  draw  lines  same  as  in 
Fig.  i. 


Take  a  pair  of  dividers,  and  from  the  bottom  of  tub  in 
profile  step  on  the  lines,  as  from  9  to  9,  8  to  8,  etc.,  making 
the  line  in  Fig.  2  equal  to  the  lines  in  profile,  stopping  where 
the  curved  line  a  crosses.  A  line  traced  through  the  dots 
will  give  the  pattern,  is  the  foot,  which  is  drawn  the  same  as 
the  other,  with  the  exception  of  drawing  the  lines  through.i 

A  VERY  durable  black  paint  for  out-of-door  work,  and  for 
many  other  purposes,  is  made  by  grinding  powdered  charcoal 
in  linseed  oil,  with  sufficient  litharge  or  drier.  Thin  for  use 
with  boiled  linseed  oil. 


408 
TRANSMISSION  IN  ENGLAND. 

According  to  the  London  Engineer,  a  fly-rope  apparently 
was  first  used  in  England  in  1863,  by  Mr.  Ramsbottom,  for 
driving  cranes  at  Crewe.  These  ropes  were  ^  inch  in  diam- 
eter when  new,  of  cotton,  and  weighing  \l/2  ounces  per  foot. 
They  lasted  about  eight  months,  and  ran  at  3,000  per  minute. 
The  total  lengths  of  the  rope  were  800  feet,  320  feet  and  560 
feet.  The  grooves  in  the  pulley  were  V-shaped,  at  an  angle 
of  30°.  The  cord  was  supported  every  12  feet  or  14  feet  by 
flat  pieces  of  chilled  cast  iron.  The  actual  power  strain  on 
\he  rope  was  about  17  pounds,  and  the  ropes  were  kept  tight 
by  a  pull  of  109  pounds  put  on  by  a  jockey  pulley.  Rope- 
geftring  is  now  superseding  belting  and  gearing  in  cotton 
mills.  It  has  long  been  used  in  South  Wales  for  driving 
helve  hammers  in  tin-plate  mills.  The  ropes  are  usual. y 
about  5^  inches  to  6j^  inches  in  circumference,  of  hemp. 
The  diameter  of  the  pulleys  shouVl  be  at  least  30  times  that 
of  the  rope,  and  the  shafts  should  not  be  less  than  20  feet 
apart.  A  6^-inch  rope  is  about  equivalent  to  a  leather  belt 
4  inches  wide,  running  at  the  same  speed — 3,000  feet  per 
minute.  Such  a  rope  will  transmit  25  horse-power.  The 
coefficient  of  resistance  to  slipping  of  a  rope  in  a  groove  is 
about  four  times  that  of  an  equivalent  belt. 

HEAT-PROOF  PAINTS. 

Steam  pipes,  steam  chests,  boiler  fronts,  smoke  connec- 
tions and  iron  chimneys  are  often  so  highly  heated  that  the 
paint  upon  them  burns,  changes  color,  blisters  and  often 
flakes  off.  After  long  protracted  use,  under  varying  circum- 
stances, it  has  been  found  that  a  silica-graphite  paint  is  well 
adapted  to  overcome  these  evils.  Nothing  but  boiled  linseed 
0/7  it  required  to  thin  the  paint  to  the  desired  consistency  for 
application,  no  dryer  being  necessary.  This  paint  is  applied 
in  the  usual  manner  with  an  ordinary  brush.  The  color,  of 
course,  is  black.  But  another  paint,  which  admits  of  some 
variety  in  color,  is  mixed  by  making  soapstone,  in  a  state  of 
fine  powder,  with  a  quick  drying  varnish  of  great  tenacity 
and  hardness.  This  will  give  the  painted  object  a  seemingly 
enamele  1  surface,  which  is  durable,  and  not  affected  by  heat, 
acids,  or  the  action  of  the  atmosphere.  When  applied  to 
wood  it  prevents  rotting,  and  it  arrests  disintegration  when 
applied  to  stone.  It  is  well  known  that  the  inside  of  an  iron 
ship  is  much  more  seve-e'y  affected  bv  corrosion  than  the 
outside,  and  this  paint  has  proven  itself  to  be  a  most  efficient 
protection  from  inside  corrosion.  It  is  light,  of  fine  grain, 


409 

can  be  tinted  with  suitable  pigments,  spread?  easily,  and 
takes  hold  of  the  fiber  of  the  iron  or  steel  quickly  and  tena- 
ciously. 

A  cheap  and  effective  battery  can  be  made  by  dissolving 
common  soap  in  boiling  water  and  adding  to  it  small  amounts 
of  bran  and  caustic  potash  or  soda.  This  mixture,  while 
warm,  is  poured  in  a  jar  containing  a  large  carbon  pole  and 
an  amalgamated  zinc  rod.  When  cold  the  battery  "sets" 
after  the  manner  of  a  jelly,  and  consequently  will  not  readily 
evaporate  or  spill  over. 

NEW    PROCESS    FOR    WIRE    MANUFACTURE. 

A  machine  for  cheapening  and  improving  steel  or  iron 
wire  has  been  invented,  which  is  calculated  to  make  a  change 
in  many  branches  of  industry  in  which  iron,  steel,  copper 
and  brass  wire  are  used.  The  invention,  which  has  just  been 
patented,  consists  of  a  series  of  rolls  in  a  continuous  train, 
geared  with  a  common  driver,  each  pair  of  rolls  having  a 
greater  sp^ed  than  the  pair  preceding  it,  with  an  intervening 
friction  clutch  adapted  to  graduate  the  speed  of  the  rolls  to 
the  speed  of  the  wire  in  process  of  rolling.  The  entire  pro- 
cess of  manufacturing  the  smallest-sized  wires  from  rods  of 
one-half  inch  is  done  cold.  The  new  process  obviates  the 
danger  of  unequal  annealing,  and  of  burning  in  the  furnaces, 
and  the  wire  is  claimed  to  be  more  flexible  and  homogeneous 
than  that  produced  by  the  common  processes,  and  capable  of 
sustaining  greater  longitudinal  strain.  It  is,  therefore, 
specially  adapted  for  screws,  nails,  cables,  pianofortes,  and 
many  other  uses,  and  copper  wire  made  by  this  process  is 
claimed  to  be  possessed  of  greatly  increased  electrical  con- 
ductivity. 

~T  EEPERS  USED  BY  THE  WORLD'S  RAILROADS. 

According  to  the  Moniteur  Industrie^  the  six  principal 
railways  of  France  use  more  than  10,000  wooden  sleepers  per 
day,  or  3,650,000  per  annum.  As  a  tree  of  ordinary  dimen- 
sions will  only  yield  ten  sleepers,  it  will  be  necessary  to  cut 
down  1,000  trees  per  day.  In  the  United  States  the  con- 
sumption is  much  greater,  amounting  to  about  15000,000 
sleepers  per  year,  which  is  equivalent  to  the  destruction  of 
170,000  acres  of  forest,  The  annual  consumption  of  sleepers 
by  the  railways  of  the  world  is  estimated  at  40,000,000. 
From  these  figures  the  rapid  progress  of  disfores'ation  will 
be  understood,  and  it  is  certain  that  the  natural  growth  can- 
not keep  pace  with  it. 


4io 

WEIGHTS  OF  CAST  IRON   PIPES. 

Weights,  per  foot,   of  Cast  Iron  Pipes  in  general  use, 
including  Socket  and  Spigot  ends. 


Diameter. 

Thickness. 

Wefeht 
per  foot. 

Diameter. 

Thickness 

x^cijriii 
per  loot. 

g  inches. 

»4-Kfncli. 

ej4  ii.s. 

14  inches 

%  inch. 

138  Ihs. 

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POINTS  FOR  BUILDERS, 

BY    STEEL    SOU  ARK. 

Never  compete  with  a  "  botch  "  if  you  know  he  is  favored 
by  the  person  about  to  build.  He  will  undercut  and  beat 
you  every  time. 

Favor  the  man  who  employs  an  architect.  ''•  Under  an 
honest  architect  you  will  have  less  friction,  make  more 
money,  be  better  satisfied  with  your  work,  and  give  greater 
satisfaction  to  the  owner  than  in  working  from  plans  fur- 
nished by  a  nondescript. 

In  tearing  down  old  -work,  be  as  careful  as  putting  up 
new. 

Old  material  should  never  be  destroyed  simply  because  it 
is  old. . 

When  putting  away  old  stuff,  see  that  it  is  protected  from 
rain  and  the  atmosphere. 

It  costs  about  fifteen  per  cent,  extra  to  work  up  old  ma- 
terial, and  this  fact  should  be  borne  in  mind,  as  I  have  known 
several  contractors  who  paid  dearly  for  their  "  whistle  "  in 
estimating  on  working  up  second-hand  material. 

These  remarks  apply  to  woodwork  only.  In  using  old 
brick,  stone,  slate  and  other  miscellaneous  materials,  it  is  as 
well  to  add  double  price  for  working  up. 

Workmen  do  not  care  to  handle  old  material,  and  justly 
so.  It  is  ruinous  to  tools,  painful  to  handle,  and  very  de- 
structive to  clothing. 

In  my  experience  I  always  found  it  pay  to  advance  the 
wages  of  workmen  —  skilled  mechanics  —  while  working  up 
old  material.  This  encouraged  the  men  and  spurred  them 
to  better  efforts. 

Sash  frames,  with  sash  weights,  locks  and  trim  complete, 
may  be  taken  out  of  old  buildings  that  are  being  taken  down 
and  preserved  just  as  good  as  new  by  screwing  slats  and 
braces  on  them,  which  not  only  keep  the  frame  square,  but 
prevent  the  glass  from  being  broken. 

Doors,  frames  and  trims  may  also  be  kept  in  good  order 
until  used,  by  taking  the  same  precautions  as  in  window 
frames. 

Old  scantlings  and  joists  should  have  all  nails  drawn  or 
hammered  i.i  before  piling  away. 

Counters,  shelving,  draws  and  other  store-fittings  should  be 


412 

kindly  dealt  with.     They  will  all  be  called  for  sooner  *r 
later. 

Take  care  of  the  locks,  hinges,  bolts,  keys,  and  other  hard- 
ware. Each  individual  piece  represents  money  in  a  greater  or 
less  sum. 

Old  flooring  can  seldom  be  utilized,  though  I  have  seen  it 
used  for  temporary  purposes,  such  as  fencing,  covering  of 
veranda  floors,  while  finishing  work  on  plastering,  etc.  As 
a  rule,  however,  it  does  not  pay  to  take  it  up  carefully  and 
preserve  it. 

Conductor  pipes,  metallic  cornices,  and  sheet  metal  work 
generally  can  seldom  be  made  available  a  second  time,  though 
all  is  worth  caring  foi,  as  some  parties  may  use  it  in  repairs. 

Sinks,  wash-basins,  bath-tubs,  traps,  heating  appliances, 
grates,  mantels  and  hearth-stones  should  be  moved  with  care. 
They  are  always  worth  money  and  may  be  used  in  many 
places  as  substitutes  for  more  inferior  fixings. 

Marble  mantels  require  the  most  careful  handling. 

Perhaps  the  most  difficult  fixtures  about  a  house  to  adapt  a 
second  time  are  the  stairs.  Yet,  I  have  known  where  a 
shrewd  contractor  has  so  managed  to  put  up  new  building's 
that  the  old  stairs  taken  from  another  building  just  suited. 
This  may  have  been  a  "  favorable  accident,"  but  the  initiated 
reader  will  understand  him.  Seldom  such  accidents  can 
occur. 

Rails,  balusters  and  newels  may  be  utilized  much  readier 
than  stairs,  as  the  rail  may  be  lengthened  or  shortened  to  ~;uit 
variable  conditions. 

Gas  fixtures  should  be  cared  for  and  stowed  away  in  some 
dry  place.  They  can  often  be  made  available,  and  are  easily 
renovated  if  soiled  or  tarnished. 

It  is  not  wise  to  employ  men  to  take  down  buildings  who 
who  have  no  other  qualities  to  recommend  them  than  their 
strength.  As  a  rule  they  are  like  bears — have  more  strength 
than  knowledge,  and  the  lack  of  the  latter  is  often  an  ex- 
pensive desideratum.  Employ  fcr  taking  down  the  work 
good,  careful  mechanics,  and  do  not  have  the  work  "  rushed 
through."  Rushers  of  this  sort  are  expensive. 

Never  send  old  material  to  a  mill  to  be  sawed  or  planed. 
No  matter  how  carefully  nails,  pebbles  and  sand  have  been 
hunted  for,  the  saw  or  planer  knives  will  most  assuredly 
find  some  you  overlooked;  then  there  will  be  trouble  at  the 
mill. 

Have  some  mercy  for  the  workman's  tools.  If  it  can  be 
avoided,  do  not  work  up  old  stuff  into  fine  work.  If  not 


413 

avoidable,  pay  the  workman  something  extra  because  of  in* 
jury  to  tools. 

Don't  grumble  if  you  do  not  get  as  good  results  from  the 
use  of  old  material  as  from  new.  The  workman  has  much 
to  contend  with'  while  working  up  old,  nail-speckled,  sand- 
covered  material. 

RULES   FOR  ESTIMATING   COST   OF   PLASTER. 
ING  AND  STUCCO  WORK. 

PLASTERING. 

Plastering  is  always  measured  by  the  square  yard  for  aV 
plain  work,  and  by  the  foot  superficial  for  all  cornices  of 
plain  members,  and  by  foot  lineal  for  enriched  or  carved 
moldings  in  cornices. 

By  plain  work  is  meant  straight  surfaces  (like  ordinary 
walls  and  ceilings),  without  regard  to  the  style  or  quantity  of 
finish  put  upon  the  job.  Any  paneled  work,  whether  on 
walls  or  ceilings,  run  with  a  mold,  would  be  rated  by  the 
foot  superficial. 

Different  methods  of  valuing  plastering  find  favor  in 
different  portions  of  the  country.  The  following  general 
rules  are  believed  to  be  equitable  and  just  to  all  parties: 

Rule  i.  —  Measure  on  walls  and  ceilings  the  surface 
actually  plastered  without  deducting  any  grounds  or  any 
openings  of  less  extent  than  seven  superficial  yards. 

Rule  2. — Returns  of  chimney  breasts,  pilasters  and  all 
strips  of  plastering,  less  than  12  inches  in  width,  measure  as 
12  inches  wide;  and  where  the  plastering  is  finished  down 
upon  the  wash-board,  surbase  or  wainscoting,  add  6  inches  to 
height  of  wall. 

Rule  3. — In  closets,  add  one-half  to  the  measurement ; 
01,  if  shelves  are  put  up  before  plastering,  charge  double 
measurement.  Raking  ceilings  and  soffits  of  stairs,  add  one- 
half  to  the  measurement.  Circular  or  elliptical  work,  charge 
two  prices  ;  domes  or  groined  ceilings,  three  prices. 

Rule  4. — For  each  12  feet  interior  work  is  done  further 
from  the  ground  than  the  first  12  feet,  add  five  per  cent. 
For  outside  work,  add  one  per  cent,  for  each  foot  the  work 
is  done  above  the  first  12  feet. 

STUCCO   WORK. 

Rule  i. — All  moldings,  less  than  one  foot  girt,  to  be 
rated  as  one  foot  ;  over  one  foot,  to  be  taken  superficial. 
When  work  requires  two  molds  to  run  same  cornice,  add 
one-fifth. 


4H 

Rule  2. — For  each  internal  angle  or  miter,  add  one  foot 
to  length  of  cornice ;  and  each  external  angle  add  two  feet. 
All  small  sections  of  cornice  less  than  12  inches  long  measure 
as  12  inches.  For  raking  cornices  add  one-half.  Circular  or 
elliptical  work,  double  price  ;  domes  and  groins,  three  prices. 

Rule  j. — For  enrichments  of  all  kinds,  charge  an  agreed 
price. 

Rule  4. — For  each  12  feet  above  the  first  12  feet  from 
the  ground,  add  five  per  cent. 

CHINESE  CASH. 

A  large  number  are  engaged  in  molding,  casting  and  fin- 
ishing the  "cash"  used  as  .coin  all  over  China,  Mexican 
dollars  and  Sycee  silver  being  used  in  large  transactions.  The 
cash  are  made  from  an  alloy  of  copper  and  zinc,  nearly 
the  same  as  the  well-known  Munn  metal,  and  it  takes 
about  1,000  of  them  to  answer  as  change  for  a  dollar,  so 
minute  and  low  do  prices  run  in  this  country,  of  which  1  will 
only  give  one  instance.  The  fare  for  crossing  the  ferry  on  the 
Peiho  was  only  two  cash,  or  one-fifth  of  a  cent. 

DEEP    SOUNDINGS    NEAR    THE   FRIENDLY 
ISLANDS. 

Her  Majesty's  surveying  ship  Egeria,  under  the  com- 
k»...nd  of  Captain  P.  Aldrich,  R.  N.,  has,  during  a  recent 
sounding  cruise  and  search  for  reported  banks  to  the  south  of 
the  Friendly  Islands,  obtained  two  very  deep  soundings  of 
4,295  fathoms  and  4,430  fathoms,  equal  to  five  Eng- 
lish miles  respectively,  the  latter  in  latitude  ^4  deg. 
37  min.  S.,  longitude  175  deg.  8  min.  W. ,  ;e  other 
about  twelve  miles  to  the  southward.  The/  .*  depths 
are  more  than  1,000  fathoms  greater  than  •  y  before 
obtained  in  the  Southern  Hemisphere,  ant-'  are  only 
surpassed,  as  far  as  is  yet  known,  in  three  spots  in  the 
the  world — one  of  4,655  fathoms  off  the  northeast  coast  of 
Japan,  found  by  the  United  States  steamship  Tuscarora  ; 
one  of  4,475  fathoms  south  of  the  Ladrone  Islands  by  the 
Challenger;  and  one  of  4,561  north  of  Porto  Rico,  by  the 
United  States  ship  Blake.  Captain  Aldrich's  soundings 
were  obtained  with  a  Lucas  sounding  machine  and  galvan- 
ized wire.  The  deeper  one  occupied  three  hours,  and 
was  obtained  in  a  considerably  confused  sea,  a  specimei) 
of  the  bottom  being  successfully  recovered.  Temperature 
of  the  bottom,  33.7  deg.  Fahr. 


415 
SIZE  AND  WEIGHT  OF  FLAT-TOP    CANS. 

The  following  table  gives  the  size  of  the  flat  top  cans  and 
the  amount  of  material  required  when  galvanized  iron  is  used 
in  their  construction.  The  table  shows  the  net  weight  per 
can  with  iron  from  No.  27  gauge  to  No.  20  gauge.  No  al- 
lowance is  made  for  seams,  hoops,  or  solder. 


SIZE    CANS. 

WEIGHT  1'ER  CAN. 

No. 

No. 

No. 

No. 

No. 

No. 

No. 

N- 

27  G. 

26  G. 

25  G. 

24  G. 

230. 

22     G. 

"   G>*    ^ 

O 
6 

g  i 

.S*| 

Height 
Inches. 

3  5 

3   o 

*            ,1     ~     "" 

3  3 

3   o 

_Q          N 

H-3      O 

3   o- 

*,    6" 

3   o 

i 

6*/4 

*K 

i       6 

i       7 

2 

%Vz 

8^ 

2          2 

2       4 

3 

9 

11^ 

2       I3 

3       o 

5 

i°/^ 

13%: 

3       13 

4        2 

4       6 

4     14 

5       7 

5     J5 

6      9 

7       6 

5 

nK 

ijK 

3     13 

4        2 

4       6 

4     Hi   5       7 

5     15 

6       9 

7      6 

6 

ii^ 

13!^ 

4       3 

4       8 

4     12 

5       6 

5     J5 

6       9 

7       2 

8       i 

8 

13* 

13^ 

5       4 

5      *o 

6       o 

6        12 

7       8 

8       9 

9 

IO          I 

10 

13^2 

165^ 

6       o 

6       7 

6     14 

7     12 

8       9 

9       7 

10       5 

ii       9 

15 

lsK 

9 

7     is|  8       8 

9       i 

10       3 

IT       5 

12       7 

13       9 

15       4 

20 

IIIA 

igl/2, 

9       8|io       2 

10     13 

12       3 

13       8 

14       4 

16       3 

18       4 

20 
25 

16 
18 

23 

9       8|io       2  10     13 

12       3 

13       8 

14       4 

16       3  18       4 

30 

26^ 

12        10 

13       8  14       7 

16       4 

18       o 

J9     X3 

21        IO  23        II 

35 

181^  y>Y> 

14       o  15       o  1  6       o 

18       o 

20       o 

22          0 

24       o  27       o 

40 

18^34  " 

15       9 

16     10 

17     ii 

19    is 

22           2 

24       6 

26       9  29     14 

45 

19^135 

16     10 

17     13 

19      o  21       6 

23        12 

26          2 

28       8  32       i 

So 

20^  35 

17     ii 

l8        15   20          3  22        12 

25       4 

27        I3 

30       5 

34       2 

55  21% 

36 

18     14 

20       6  21     10  24       3 

26       7 

29       12 

32       736      8 

6022 
6522^ 

38 

20          3 
21          3 

21        IO  23          O 

22       9  24       3 

25     15 
27       4 

28        12 

30       5 

31        IO 

33       6 

34       8 
36       5 

38     13 
40     14 

7023 

40 

22       IO  24          4  25       13 

29       i 

32       5 

35       8 

38       12 

43       9 

75  23  1A  40 

23     '  3 

24     14  26       9  29     13  33       2 

36       7 

39     i3 

44     J3 

8024^ 
8525 

40 

40 

24       7 
25        i 

26       3 
26     14 

27     15  31       7 
28     10  32       7 

34     J5 
35     13 

38       6 
39       6 

4i     15 

43       ° 

47       3 
48       5 

9024^ 

45 

26     13 

28     ii 

30     10 

34       7 

38       4 

42       i 

45     i5 

95  25 

45 

27       7 

29       6 

31       5 

35       4 

39       3 

43       i 

47       o  52     14 

100  26 

45 

28     13 

30     14 

32     14 

37       o 

41       2 

45       4 

49       6(55       9 

I25  27^ 

50 

33       8 

35     i5 

38       5 

43       2 

47     M 

52     ii 

57       7,64     I0 

150  29 

52^ 

37       i 

39     12 

42       6 

47     ii 

52     15 

58       4 

63       9!  71       9 

J75  3° 
20030%; 

64  2 

41       9 
46       6 

44       8 
49     12 

47        7 
53       3 

53       6 
59     J4 

59       5 
66       6 

65       3 

71        380       I 
79     10:89     10 

Mexican  coal  has  been  successfully  used  for  making  coke 
at  Pittsburg. 


THE   CHICAGO  AUDITORIUM. 

At  a  meeting  of  the  Chicago  Auditorium  Association  the 
president  submitted  his  report,  from  which  we  take  the  fol- 
lowing: 

To  the  Stockholders  of  the  Chicago  Auditorium  Associa- 
tion—  Your  great  undertaking  has  progressed  to  a  point  when 
a  recital  of  the  condition  of  affairs,  together  with  a  brief  his- 
tory of  the  project,  will  be  of  especial  interest  to  you. 

Ground  was  broken  and  the  work  of  tearing  down  build- 
ings was  begun  in  January,  1887.  The  constvuction  has  bee* 
vigorously  prosecuted  from  that  time,  the  only  delay  occur- 
ring from  difficulty  in  procuring  granite,  which  necessitated 
the  association  taking  possession  of  the  quarries,  the  result  of 
which  was  satisfactory.  From  the  date  of  completion  of  the 
granite  work,  comprising  the  two  stories  of  the  sub-structure, 
all  contracts  have  been  thus  far  satisfactorily  and  promptly 
carried  forward,  and  we  feel  that  we  have  been  exceptionally 
fortunate  in  the  selection  of  all  the  contractors,  especially  so 
of  the  architects,  who  have  faced  most  difficult  and  unprece- 
dented problems. 

This  enterprise,  like  all  large  projects,  has  been  a  matter 
ot  growth  and  development  from  its  inception,  both  in  mag- 
nitude and  cost,  and,  in  the  judgment  of  your  board,  it  has 
been  in  every  instance  wise.  It  was  originally  contemplated 
by  the  projectors  that  a  great  public  hall  and  a  hotel  should 
be  built  on  a  site  not  including  the  corner  of  W abash  avenue 
and  Congress  street  and  the  north  lot  of  the  Michigan  avenue 
frontage,  which  were  not  then  obtainable.  From  that  your 
building  has  grown  to  cover  the  entire  site  now  occupied  — 
710  feet  frontage,  or  an  area  of  one  and  five-eighths  acres. 
Strict  fire-proof  construction  of  the  most  approved  kind  was 
always  contemplated,  and  it  prevails  throughout  the  entire 
structure  ;  so  that  under  no  circumstances  can  your  building 
sustain  more  than  slight  superficial  injury  from  fire.  The 
tenth  story  has  recently  been  changed  to  make  it  one  foot 
higher,  and  one  story  has  been  added  to  the  plans  of  the 
tower  this  summer. 

With  the  grandeur  of  the  rising  building  developed  the 
necessity  of  absolutely  first-class  treatment  in  details  and 
interior  finish.  The  hotel  rooms  will  be  finished  in  hard- 
wood throughout ;  mosaic  floors  will  be  laid  in  the  vestibule 
and  lobby  in  the  Auditorium  and  hotel.  The  grand  stair- 
way will  be  marble,  writh  bronze  sides.  An  extra  elevator 
was  recently  decided  upon,  making  twelve  in  all,  nine  passen- 
ger and  three  freight. 


4*7 

A  grand  organ,  costing  about  $50,000,  was  contracted 
for,  and  is  being  built  probably  at  a  loss  to  the  contractor, 
the  contract  for  which  calls  for  the  most  complete  and 
grandest  instrument  ever  constructed,  and  which  your  board 
believes  will  do  much  for  musical  education  in  this  city,  and 
add  largely  to  the  earnings  of  your  Auditorium — more  than 
ordinary  interest  on  its  cost. 

It  was  also  determined  to  adopt  the  most  approved  and 
modern  stage,  with  appointments  similar  to  one  at  Buda- 
Pesth,  Hungary,  for  which  purpose  Architect  Adler  was  sent 
to  Europe,  and  Mr.  Bairstow,  chief  stage  carpenter  for 
McVicker's  theater  for  many  years,  was  employed,  and 
accompanied  him  abroad.  This  will  cost  much  more  than 
the  ordinary  stage,  but  will  be  unequaled  on  either  continent 
in  its  effects  and  operating  economies,  and  it  is  regarded  a 
judicious  step  by  your  board,  as  it  constitutes,  in  theatre 
parlance,  a  permanent  attraction. 

Then  there  are  the  devices  of  heavy  ironwork  for  shutting 
off  the  galleries  and  part  of  the  main  balcony,  lessening  the 
cubic  contents  of  our  hall,  thereby  adapting  it  for  many  pur- 
poses for  which  otherwise  it  could  not  well  be  used.  This 
nas  added  considerably  to  cost  of  ironwork. 

A  few  statistics  respecting  your  structure,  about  which  so 
many  questions  are  asked,  may  be  of  interest  to  you.  It  com- 
prises five  principal  features  —  the  auditorium,  with  its  grand 
organ  and  stage;  the  hotel;  the  business  front  on  Wabash 
avenue,  containing  seven  stories  and  nine  floors  of  rooms;  the 
fettle' auditorium,  or  rehearsal  hall;  and  the  public  observa- 
tory. To  which  might  be  added  the  cafe  cm  the  main  floor 
on  Congress  street.  The  main  building  will  be  ten  stories 
high,  or  145  feet,  the  auditorium  proper  reaching  the  seventh 
story.  The  tower  will  be  seventeen  stories  high,  or  240  feet. 
The  foundations  under  your  buildings  have  been  carefully  and 
scientifically  considered.  Every  square  yard  of  the  ground 
was  first  tested  by  heavy  water-tanks,  then  horizontal  tim- 
bers of  varying  lengths,  one  square,  were  laid  permanently 
below  the  water-line,  covering  whi  h  is  a  heavy  bed  of  con- 
crete, in  which  from  one  to  four  layers  of  67-pound  steel 
rails  are  imbedded.  These,  if  placed  in  line,  would  reach  ten 
miles  in  length.  Where  the  rails  were  insufficient  in  strength, 
steel  I-beams  were  substituted  for  them.  Upon  these  rails 
and  beams  the  piers  were  constructed.  The  tower  rests  on 
a  solid  foundation,  100x67  feet,  thus  distributing  the  weight 
over  a  larger  surface.  The  auditorium  will  contain  5,000  seats, 
including  forty-two  boxes.  This  capacity  can  be  largely 
increased  for  conventions  by  utilizing  the  stage  space.  The 


418 

hotel  will  occupy  the  entire  Michigan  avenue  and  congress 
street  fronts,  and  forty  feet  of  Wabash  avenue  front,  and 
will  contain  nearly  400  rooms.  The  main  dining-room  will 
be  on  the  tenth  floor  of  the  east  front,  175  feet  long,  over- 
looking the  lake.  There  will  be  twelve  elevators  in  all. 
The  cost  of  the  iron  in  the  building  is  nearly  $350,000,  no 
portion  of  which  will  be  visible.  The  number  of  brinks  in 
the  building  is  15,000,000. 

The  number  of  electric  lights  in  the  auditorium  proper 
is  4,000;  in  the  hotel  and  balance  of  the  building,  4,600; 
making  8,600  in  all.  The  electric  current  is  generated  by 
eleven  dynamos  and  nine  engines ;  there  will  be  eleven 
boilers,  having  a  capacity  of  1,800  horse-power;  and 
twenty-one  pumping  engines  to  supply  water  fur  the 
elevators  and  other  purposes,  with  a  total  hourly  capacity  of 
400,000  gallons.  There  are  two  distinct  heating  and  lighting 
plants  for  the  hotel  and  balance  of  building.  The  tower 
weighs  30,000,000  pounds,  or  15.000  tons.  There  are  over 
twenty-five  miles  of  gas  and  water  pipes. 

To  calculate  number  of  shingles  for  a  roof,  ascertain  num- 
ber of  square  feet  and  multiply  by  4;  if  2  inches  to  weather, 
8  for  4^  inches,  and  7  1-5  if  5  inches  are  exposed.  The 
length  of  rafter  of  one  third  pitch  is  equal  to  three-fifths  of 
width  of  building,  adding  projection. 

PAINTWORK. 

Tt  may  be  useful  to  know  that  a  gallon  of  paint  will  cover 
from  450  to  630  superficial  feet  of  wood.  On  a  well-painted 
surface  of  iron  the  gallon  will  cover  720  feet.  In  estimating 
painting  to  old  work,  the  first  thing  to  do  is  to  find  out  the 
nature  of  the  surface,  whether  it  is  porous,  rough  ot  smooth, 
hard  or  soft.  The  surface  of  stucco,  for  example,  will  take  a 
great  deal  more  paint  than  on  of  wood,  much  depending  on 
the  circumstance  whether  it  has  been  painted,  and  what  state 
the  surface  is  in.  We  have  known  prices  tendered  for  outside 
painting  that  have  been  seriously  wrong,  owing  to  the  want 
of  knowing  the  condition  of  the  stucco  work.  A  correct  e  Mi- 
niate of  repainting  woodwork  cannot  be  made  from  the  quan- 
tities only;  a  personal  examination  ought  to  be  made  in  every 
tase  where  there  is  much  work  to  be  done.  A  great  many 
painters  trust  to  the  quantity;  the  consequence  is,  nothing  is 
allowed  to  remove  old  paint,  or  for  scouring,  and  the  stopping 
of  cracks. 

Then,  there  is  painting  and  painting.  It  can  be  done  well 
and  artistically,  or  indifferently,  and  few  trades  allow  of 
greater  scamping.  In  first-class  work,  after  the  first  two  coats 


419 

have  been  put  on,  the  paint,  when  dry,  should  be  rubbed 
down  with  pumice-stone  before  the  finishing  coats  are  put  on. 
Inferior  painting  is  so  common  that  it  has  «  fj.emoralizing  effect 
on  painters  of  the  day.  The  quality  of  tue  material,  especially 
the  white  lead,  has  much  to  do  with  the  permanency.  We 
find  painting  done  on  old  work  without  any  cleaning,  stopping 
or  even  pumicing.  A  slovenly  and  inartistic  class  of  Drainers 
are  also  met  with,  who  repaint  and  '-e^rain  on  work  that 
ought  to  bi  well  rubbed  with  pumice-sione  or  sand-paper  be- 
fore the  first  new  coat  is  laid. 

For  painting  three  coats  the  following  materials  are  given 
for  ioo  superficial  feet  of  ne\v  work:  Paint,  eight  pounds; 
boiled  linseed  oil,  three  pints;  spirits  of  turpentine,  one  ]  int; 
the  work  taking  thre  men  for  one  clay.  According  (o  Saxton, 
forty-five  yards  of  first  coat,  including  stopping,  will  require 
five  pounds  of  white  lead,  five  pounds  of  putty,  one  quart  of 
oil.  The  same  quantity  of  each  succeeding  coat  will  require 
the  same  allowance  of  white  lead  and  oil.  The  best  materials 
will  last  for  seven  years,  but  the  ordinary  painting  seldom  lasts 
three. 

THE  ANNUAL  KING  IX  TREES. 

The  annual  rings  in  trees  exist  as  such  in  all  timber  grown 
in  the  temperate  zone.  Their  structure  is  so  different  in 
different  groups  of  timber  that,  from  their  appearance  alone, 
the  quality  of  the  timber  may  be  judged  to  some  extent. 
For  this  purpose  the  absolute  width  of  the  rings,  the  regu- 
larity in  width  from  year  to  year  and  the  proportion  of  spring 
wood  to  autumn  wood  must  be  taken  into  account.  Spring 
wood  is  characterized  by  less  substantial  elements,  the  ves- 
sels of  thin-walled  cells  being  in  greater  abundance,  while 
autumn  wood  is  formed  of  cells  with  thicker  walls,  which 
appear  darker  in  color.  In  conifers  and  deciduous  trees  the 
annual  rings  are  very  distinct,  while  in  trees  like  the  birch, 
linden  and  maple  the  distinction  is  not  so  marked,  because 
the  vessels  are  more  evenly  distributed.  Sometimes  the 
gradual  change  in  appearance  of  the  annual  ring  from  spring 
to  autumn  wood,  which  is  due  to  the  difference  in  its  compo- 
nent elements,  is  interrupted  in  such  a  manner  that  a  more  or 
less  pronounced  layer  of  autumn  wood  can  apparently  be 
recognized,  which  again  gradually  changes  to  spring  or  sum- 
mer wood,  and  then  gradually  finishes  with  the  regular  autumn 
wood.  r\  his  irregularity  may  occur  even  more  than  once  .,i 
the  same  ring,  and  this  has  led  to  the  notion  that  the  annual 
rings  are  not  a  true  indication  of  age;  but  the  double  or 


42° 

counterfeit  tings  can  be  distinguished  by  a  practiced  eye  with 
the  aid  of  a  magnifying  glass.  These  irregularities  are  due 
to  some  interruptions  of  the  functions  of  the  tree,  caused  by 
defoliation,  extreme  climatic  condition  or  sudden  changes  of 
temperature.  The  breadth  of  the  ring  depends  on  the  length 
of  the  period  of  vegetation;  also  when  the  soil  is  deep  and  rich, 
and  light  has  much  influence  on  the  tree,  the  rings  will  be 
broader.  The  amount  of  light,  and  the  consequent  development 
of  foliage,  is  perhaps  the  most  powerful  factor  in  wood  forma- 
tions, and  it  is  upon  the  proper  use  of  this  that  the  forester 
depends  for  his  means  of  regulating  the  development  and 
quantity  of  his  crop. 

POINTERS    FOR   ARCHITECTS,  BUILDERS   AND 
WOOD-WORKERS. 

A  box  of  window-glass  contains  fifty  feet  of  glass,  regard- 
less of  size  of  sheets. 

African  teak-wood  outlasts  any  other  kind  of  wood.  It 
is  the  only  wood  found  preserved  in  Egyptian  tombs  4,0x30 
years  old.  It  shrinks  only  "  on  end. " 

It  is  a  common  practice  in  France  to  coat  the  beams,  the 
joists  and  the  under  side  of  the  flooring  of  buildings  with  a 
thick  coating  of  lime- wash  as  a  safeguard  against  fire.  It  is 
a  preventive  of  prime  ignition,  although  it  will  not  check  a 
fire  when  once  under  headway. 

Any  beam,  whether  of  wood  or  iron,  is  as  much  stronger 
when  placed  on  its  edge  as  when  on  its  side,  as  the  width  is 
greater  than  he  thickness.  Thus  a  stick  or  bar  of  iron  one 
inch  by  three  inches  when  used  as  abeam  is  three  limes  as 
strong  when  placed  on  its  edge  as  when  on  its  side.  This  is 
true  only  within  limits.  It  would  not  be  true  of  a  piece  of 
boiler-plate,  on  account  of  the  flexibility. 

Mortar  made  in  the  following  manner  will  stand  if  used  in 
almost  all  sorts  of  weather :  One  bushel  of  unslaked  lime, 
three  bushels  of  sharp  sand  ;  mix  I  Ib.  of  alum  with  one  pint 
of  linseed  oil,  and  thoroughly  mix  this  with  the  mortar  when 
making  it,  and  use  hot.  The  alum  will  counteract  the  action 
of  the  frost  on  the  mortar. 

A  new  system  of  building  houses  of  steel  plates  is  being 
introduced  by  M.  Danly,  manager  of  the  Societe  des  Forges 
de  Chateleneau  It  has  been  found  that  corrugated  sheets 
only  a  millimetre  in  thickness  are  sufficiently  strong  for  build- 
ing houses  several  stories  high,  and  the  material  used  allows 
of  architectural  ornamentation.  The  plates  used  are  of  the 


42I 

finest  quality,  and  as  they  are  galvanized  after  they  have  been 
cut  to  the  sizes  and  shapes  required,  no  portion  is  left 
exposed  to  the  action  of  the  atmosphere.  Houses  so  con- 
structed are  very  sanitary,  and  the  necessary  ventilating  and 
heating  arrangements  can  readily  be  carried  out. 

Moisture-proof  glue  is  made  by  dissolving  16  ounces  of 
glue  in  3  pints  of  skim  milk.  If  a  still  st  ronger  glue  be  want- 
ed, add  powdered  lime. 

Shellac  and  borax  boiled  in  water  produces  a  good  stain 
for  floors. 

Don't  inclose  the  sink  —  no  place  in  a  kitchen  is  so 
much  neglected. 

Porch  floors  should  be  of  narrow  stuff  and  the  joints  laid 
in  white  lead. 

Lime-water  is  fire-proof  protection  for  shingles  or  any 
light  wood-work. 

Common  brick  absorb  a  pint  of  water  each,  and  make  a 
very  damp  house. 

The  lowest -priced  builder   is  not  always  the  cheapest,  as- 
poor  work  will  testify. 

A  closet  finished  with  red  cedar  shelves  and  drawers  is 
death  to  moths  and  insects. 

Do  not  locate  a  furnace  register  next  to  a  mantel  — that 
is,  if  you  wish  to  utilize  the  heat. 

Terra-cotta  flue  linings  are  a  great  improvement  over 
the  old,  roughly  plastered  chimney. 

For  basement  fl  >oring,  oak  is  preferred  to  maple  because 
it  will  stand  dampness  better. 

To  properly  select  the  colors  applicable  to  the  proper 
place,  consult  an  educated  painter 

A  ventilating  flue  from  the  kitchen  into  the  chimney 
often  does  away  with  atmospheric  meals. 

Stops  to  doors  and  windows  should  be  fastened  with 
roundhead  screws,  so  as  to  be  easily  moved. 

It  is  better  to  oil  floors  than  to  paint  them  —  a  monthly 
rubbing  will  make  them  as  good  as  new. 

Do  not  use  one  chimney-flue  for  two  stove  pipes  —  the 
draft  of  one  will  counteract  that  of  the  other. 

Do  not  finish  windows  to  the  floor  — -the  circulation 
across  the  floor  is  one  of  the  causes  of  cold  houses. 

Ash-pits  in  cellars  under  fire-places  and  mantels  save 
taking  up  ashes,  for  they  may  be  raked  down  through  a  hop- 
per. 

Do  not  construct  solid  doors  of  two  kinds  of  hardwood 
—  the  action  of  the  atmosphere  on  one  or  the  other  will 
cause  the  door  to  warp. 


422 

HINTS  ON  VENTILATION. 

In  ventilating  —  say,  a  bed-room  —  by  means  of  the  win- 
dow, what  you  may  principally  \\ant  is  an  upward-blowing 
current.  Well,  there  are  several  methods  of  securing  this 
without  danger  of  a  draught. 

1.  Holes  may  be  bored  in   the  lower   part  of  the  upper 
sash  of  the  window,  admitting  the  outside  air. 

2.  Right  across  one  foot  of  the  lower  .-a  h.  but  attached 
to  the  immovable  frame  of  the  wind  >v.  ,  may  he  hung  or  tacked 
apiece   of  strong    Willesdeu   paper—  prettily    painte  I    \\ith 
flowers  or  birds,  if  you  please.     The    window   may  then  he 
raised  to  the  extent  of  the  breadth  of  this  ]  aner,  ;  ml   the  air 
rushes  upward  between  the  two  sashes. 

3.  The  same  effect   i;  goc    from   simply  having  a  b:>ard 
about  six  inches  \vide  and  the  exact  si/.e  of  the  sash's  !  readth. 
Use  this  to  hold  the  window  up. 

4.  This  same  board  may  have  two  bent  or  elbow  tubes  in 
it,    opening     upward    and    into    the    room,    so    that    the   air 
coming  through  does  not  blow  directly  in.     The  inside  open- 
ings may  be  protected  by  valves,  and  thus  tlv>  amount  of  in- 
coming current  can  be  regu'ated.      We  thus  get  a  circulating 
movement  of  the  air,  as,  the  window  being  raised,  there  is  an 
opening  between  the  sashes. 

^  5.  In  summer  a  frame  half  as  big  as  the  lower  <-ash  may 
be  made  of  perforated  zinc  or  wire  gau/.e  and  placed  in  so  as 
to  keep  the  window  up.  There  is  n  >  draught  ;  and,  if  kept  in 
position  all  night,  then,  as  a  rule,  the  inmate  wi'.l  enjoy  re- 
freshing sleep. 

6.  In  addition  to  these  plans,  the  door  of  every  bed- 
room should  possess,  at  the  top  thereof,  a  ventilating  panel, 
the  simplest  of  all  being  that  formed  of  wire  gauze. 

In  conclusion,  let  me  again  beg  of  you  t">  value  fresh  air 
as  you  value  life  and  health  itself;  while  taking  care  not  to 
sleep  directly  in  an  appreciable  draught,  to  abjure  curtains 
all  round  the  bed.  A  curtained  bed  is  only  a  stable  for 
nightmares  and  an  hotel  for  a  hundred  wonder-ills  and  ail- 


INVENTION  OF  THE  SCREW  AUGER. 

Tiie  screw  auger  was  invented  by  Tl  omas  Garrett  anout 
100  years  ago.  He  lived  near  Oxford,  Chester  County, 
Pennsylvania.  The  single  screw  auger  was  invented  by  a 
Philadelphia!!,  and  it  is  said  to  be  the  only  one  used  with  any 
Satisfaction  in  very  hard  woods  where  the  double  screw  augers 
become  clogged. 


423 
THE  FORESTS  OF  THE    UNITED  STATES. 

The  total  area  of  forest  lands  in  the  United  States  and 
Territories,  according  to  the  annual  report  of  the  Division 
of  Forestry  of  the  Department  of  Agriculture,  is  465,795,000 
acres.  The  State  which  has  the  largest  share  is  Texas, 
which  is  credited  with  40,000,000  acres.  Minnesota  comes 
next  with  30,000,000,  then  Arkansas  with  28,000,000;  and 
Florida,  Oregon,  California  and  Washington  Territory  are 
put  down  at  20,000,000  each.  Georgia  and  North  Carolina 
nave  each  18,000,000;  Wisconsin  and  Alabama,  each 
17,000,000;  Tennessee,  16,000,000;  Michigan,  14,000,000; 
and  Maine,  12,000,000  acres.  Taking  the  States  in  groups, 
the  six  New  England  States  have,  in  round  numbers, 
19,000,000  acres;  four  Middle  States,  18,000,000;  nine 
Western  States,  iVo,ooo.ooo;  four  Pacific  States,  53,000,000; 
seven  Territories,  63.000,000;  and  fourteen  Southern  States, 
233,000,000  acres,  or  almost  precisely  half  of  the  whole  for- 
est area  of  the  country. 

Reviewing  the  figures  given  by  the  department,  the 
Tradesman,  of  Chattanooga,  Tenn.,  makes  the  following 
instructive  comment:  "  These  statistics  show  that,  while  the 
process  of  denudation  has  been  carried  on  to  an  unhealthy 
extreme  in  the  Eastern,  Middle  and  a  few  of  the  Western 
States,  the  forest  area  still  remaining  in  this  country  is  a 
magnificent  one.  If  the  estimates  of  the  department  are 
approximately  correct,  the  timber  lands  of  the  country, 
exclusive  of  Alaska,  cover  an  area  equal  to  fifteen  States  the 
size  of  Pennsylvania.  If  proper  measures  are  taken  to  pre- 
vent the  rapid  and  unnecessary  destruction  of  what  is  left  of 
our  forest  domain,  it  should  be  equal  to  all  requirements  for 
an  indefinite  period.  It  is  not  yet  a  case  of  locking  the 
stable  after  the  horse  is  stolen,  and  never  should  be  allowed 
to  become  so.  With  the  adoption  the  policy  of  judicious 
trfee  planting  in  the  prairie  States,  and  a  system  of  State  or 
government  reservations  in  the  mountainous  districts,  which 
are  the  sources  of  the  chief  rivers  of  the  country,  the  evil 
effects  which  have  followed  forest  denudation  in  Europe  and 
some  portions  of  Asia  would  never  exist  here." 

TO  FIND  THE  WEIGHT  OF  GRINDSTONES. 

.06363  times  square  of  inches  diameter,  times  thickness 
in  inches  =  weight  of  grindstone  in  Ibs. 

3.1415926---  ratio  of  diameter  to  circumfeieuce  of  circle. 


424 

ALTITUDE  ABOVE    THE    SEA-LEVEL   OF    VARI- 
OUS PLACES  IN  THE    UNITED  STATES. 


Portland,  Me              .   . 

185 

Knoxville,  Xenn  .... 

Concord,  N    H  

•  •  •       375 

Louisville,   Ky  

' 

Cleveland,  O  

645 

480 

Detroit    Mich 

Upper  portion  of  city 

t-88 

Mt.  Washington  
Ann  Arbor   Mich.   .. 

....    6,2Q3 

800 

San  Francisco,  Cal  
Indianapolis,  Ind  .... 

130 

Boston,  Mass  

82 

Chicago,  111  

r«T 

Albany,  N.  Y  

CQQ 

New  York  N   Y 

60 

St  Anthony  Falls     Minn 

822 

Buffalo   N    Y 

580 

Dubuque    la 

Philadelphia   Penn  .  .  . 

60 

St   Louis    Mo 

/l80 

Pittsburg    Penn  

QT  tr 

Omaha    Neb 

Baltimore,  Md  

•  •  •       275 

Lawrence     Kan. 

SO-! 

Washington,!).  C.... 

.  .  .          92 

Fort  Phil  Kearney  Wy 

6  ooo 

Charleston,  S.  C  

Yankton,  Dak  

Vicksburg,  Miss  

352 

Fort  Garland,  Colo  

8  365 

New  Orleans,  La  
El  Paso,  Texas  

10 

••     3,831 

Salt  Lake  City,  Utah  
Sacramento,   Cal  

4,322 

22 

TABLE  OF  PRINCIPAL  ALLOYS. 

A  combination  of  zinc  and  copper  makes  bell  metal. 

A  combination  of  copper  and  tin  makes  bronze  metal. 

A  combination  of  antimony,  tin,  copper  and  bismuth,  makes  britannia 
metal. 

A  combination  of  copper  and  tin  makes  cannon  metal. 

A  combination  of  copper  and  zinc  makes  Dutch  gold. 

A  combination  of  copper,  nickel  and  zinc,  with  sometimes  a  little  iron 
and  tin,  makes  German  silver. 

A  combination  of -gold  and  copper  makes  standard  gold. 

A  combination  of  gold,  copper  and  silver,  makes  old  standard  gold. 

A  combination  of  tin  and  copper  makes  gun  m  >tal. 

A  combination  of  copper  and  zinc  makes  mosaic  gold. 

A  combination  of  tin  and  lead  makes  pewter. 

A  combination  of  lead  and  a  little  arsenic,  makes  sheet  metal. 

A  combination  of  silver  and  copper  makes  standard  silver. 

A  combination  of  tin  and  lead  makes  solder. 

A  combination  of  lead  and  antimony  makes  type  metal. 

A  combination  ot  copper  and  arsenic  makes  white  copper. 

HOW  TO   POLISH   ZINC. 

AVe  have  been  successful  in  polishing  zinc  with  the  follow- 
ing solution :  To  2  quarts  of  rainwater  add  3  oz.  powdered 
rotten  stone,  2  oz.  pumice  stone,  and  4  oz.  oxalic  acid.  Mix 
thoroughly,  and  let  it  stand  a  day  or  two  before  using.  Stir 
or  shake  it  up  when  using,  and,  after  using,  polish  the  zinc 
with  a  dry  woolen  cloth  or  chamois  skin.  The  more  thor- 
oughly the  zinc  is  rubbed  the  longer  it  will  stay  bright. 


425 
HOW  TO  MAKE  A  GOOD  FLOOR. 

Nothing  attracts  the  attention  of  a  person  wishing  to  rent 
or  purchase  a  dwelling,  store  or  office,  so  quickly  as  q,  hand- 
some, well-laid  floor,  and  a  few  suggestions  on  the  subject, 
though  not  new,  may  not  be  out  of  place. 

The  best  floor  for  the  least  money  can  be  made  of  yellow- 
pine,  if  the  mateiial  is  carefully  selected  and  properly  laid. 

First,  select  edge-grain  yellow  pine,  not  too  "fat,"  clear 
of  pitch,  knots,  sap  and  splits.  See  that  it  is  thoroughly 
seasoned,  and  that  the  tongues  and  grooves  exactly  match,  so- 
that,  when  laid,  the  upper  surfaces  of  each  board  are  on  a 
level.  1'his  is  an  important  feature  often  overlooked,  and 
planing-mill  operatives  frequently  get  careless  in  adjusting 
the  tonguing  and  grooving  bits.  If  the  edge  of  a  flooring 
board,  especially  the  grooved  edge,  is  higher  than  the  edge 
of  the  next  board,  no  amount  of  mechanical  ingenuity  can 
make  a  neat  floor  of  them.  The  upper  part  of  the  groove 
will  continue  to  curl  upward  as  long  as  the  floor  lasts. 

Supposing,  of  course,  the  sleepers,  or  joists,  are  properly 
placed  the  right  distance  apart,  and  their  upper  edges  pre- 
cisely on  a  level,  and  securely  braced,  the  most  important 
part  of  the  job  is  to  "  lay  "  the  flooring  correctly  %  This 
part  of-  the  work  is  never,  or  very  rarely  ever,  done  nowa- 
days. The  system  in  vogue  with  carpenters  of  this  day,  of 
laying  one  board  at  a  time,  and  "  blind  nailing,"  is  the  most 
glaring  fraud  practiced  in  any  trade.  They  drive  the  tongue 
of  the  board  into  the  groove  of  the  preceding  one,  by 
pounding  on  the  grooved  edge  with  a  naked  hammer,  mak- 
ing indentations  that  let  in  the  cold  air  or  noxious  gases,  if 
it  is  a  bottom  floor,  and  then  nail  it  in  place  by  driving  a 
six-penny  nail  at  an  angle  of  about  50°  in  the  groove.  An 
awkward  blow  or  two  chips  off  the  upper  part  of  the  groove, 
and  the  last  blow,  designed  to  sink  the  nail-head  out  of  the 
way  of  the  next  tongue,  splits  the  lower  part  of  the  groove 
to  splinters,  leaving  an  unsightly  opening.  Such  nailing 
does  not  fasten  the  flooring  to  the  sleepers,  and  the  slanting 
nails  very  often  wedge  the  board  up  so  that  it  does  not  bear 
on  the  sleeper.  We  would  rather  have  our  flooring  in  the 
tree  standing  in  the  woods  than  put  down  that  way. 

The  proper  plan  is  to  begin  on  one  side  of  the  room,  lay 
one  course  of  boards  with  ihe  tongue  next  to,  and  neatly 
fitted  to,  the  wall  (cr  studding,  if  a  frame  house),  and  be 
sure  the  boards  are  laid  perfectly  straight  from  end  to  end 
of  the  room  and  square  with  the  wall.  Then  nail  this  course 
firmly  to  the  sleepers,  through  and  through,  one  nail  near 


426 

each  edge  of  the  board  on  every  sleeper,  and  you  are  ready- 
to  begin  to  lay  a  floor.  Next,  fit  the  ends  and  lay  down 
four  or  six  courses  of  boards  (owing  to  their  width).  If  the 
boards  differ  widely  in  color,  as  is  often  the  case  in  pine,  do 
not  lay  two  of  a  widely  different  color  side  by  side,  but 
arrange  them  so  that  the  deep  colors  will  tone  off  into  the 
lighter  ones  gradually.  Push  the  tongues  into  the  grooves 
as  close  as  possible,  without  pounding  with  a  hammer,  or,  if 
pounding  is  necessary,  take  a  narrow,  short  piece  of  flooring, 
put  the  tongue  in  the  groove  of  the  outer  board,  and  pound 
gently  on  the  piece,  never  on  the  flooring  board.  Next, 
adjust  your  clamps  on  every  third  sleeper  and  at  every  end 
joint,  and  drive  the  floor  (irmly  together  by  means  of 
wedges.  IDrive  the  wedges  gently  at  the  start,  and  each  one 
equally  till  the  joints  ail  fill  up  snugly,  and  then  stop,  for,  if 
driven  too  tight,  the  fl  >or  will  spring  up.  Never  wedge 
directly  against  the  edge  of  the  flooring  board,  but  have  a 
short  strip  with  a  tongue  on  it  between  the  wedge  and  the  . 
board,  so  as  to  leave  no  bruises.  Then  fasten  the  floor  to 
the  sleepers  by  driving  a  flat- headed  steel  wire  nail  of  suit- 
able size,  one  inch  from  either  edge  of  every  board,  straight 
do\Mi  into  each  sleeper.  At  the  end-joints  smaller  nails  may 
be  used,  two  nails  in  board  near  the  edges,  and  as  far  from 
the  ends  as  the  thickness  of  the  sleeper  will  permit.  Pro- 
ceed in  this  manner  until  the  floor  is  completed,  and  you 
will  have  a  floor  that  will  remain  ti^ht  and  look  well  until 
worn  out. 

Such  minute  directions,  for  so  common  and  simple  a  job, 
sound  silly,  but  are  justifiable  from  the  fact  that  there  are  so 
many  alleged  carpenters  who  either  do  not  know  how  or  are 
too  lazy  to  lay  a  floor  properly. 

GLUE   FOR  DAMP  PLACES. 

For  a  strong  glue,  which  will  hold  in  a  damp  place,  the 
following  recipe  works  well :  Take  of  the  best  and  strongest 
glue  enough  to  make  a  pint  when  melted.  Soak  this  until 
soft.  Pour  off  the  Mater,  as  in  ordinary  glue-making,  and 
add  a  little  \\ater  if  the  glue  is  likely  to  be  too  thick.  When 
melted,  add  three  table-spoonfuls  of  boiled  Unseed  oil.  Stir 
frequently,  and  keep  up  the  heat  till  the  oil  disappears, 
which  may  take  the  whole  day,  and  perhaps  more.  If 
necessary,  add  water  to  make  up  for  that  lost  by  evaporation. 
When  no  more  oil  is  seen,  a  tablespoonful  of  whiting  is  added 
and  thoroughly  incorporated  with  the  glue. 


427 
MORTAR  MAKING.  ^ 

Much  depends  on  having  mortar  made  on  correct,  if  not 
scientific,  principles.  The  durability,  if  not  the  actual  safety, 
of  a  building  is  more  or  less  affected  by  the  kind  of  mortar 
that  is  put  into  it.  We  have  seen  brick  buildings,  and  not 
very  old  ones  either,  from  which  the  dry  and  hardened  mor- 
tar could  easily  be  picked  in  cakes  from  between  the  bricks. 
The  advantage  of  using  such  mortar  is,  that,  when  the 
building  tumbles  down,  ^ there  will  be  no  trouble  in  picking 
from  it  the  old  bricks,  preparatory  to  rebuilding.  A  brick 
wall,  if  put  up  with  the  right  kind  of  mortar,  will  be  solid 
and  almost  homogeneous,  as  likely  to  break  through  the 
middle  of  the  bricks  as  at  the  joints.  Such  a  building  will 
never  tumble  down,  except  under  great  strain,  and  will  with- 
stand a  pretty  severe  earthquake  shock. 

An  old  builder,  of  nearly  forty  years'  experience  in  mak- 
ing mortar,  writing  upon  the  subject  to  a  contemporary, 
very  justly  says:  "The  mere  matter  of  slacking  lime  does 
not  make  mortar  out  of  it.  Lime  and  water  alone  will  not 
make  any  better  mortar  than  sand  and  water."  t  He  sug- 
gests the  use  of  plenty  of  water  in  slacking  the  lime,  so 
that,  when  it  is  run  out  of  the  box  into  the  bed,  it  will  not 
bake  or  burn,  as  it  is  liable  to  do,  if  not  well  watered.  The 
mortar  bed  should  be  large  and  tight,  so  there  will  be  no 
leakage  of  the  lime  water.  The  proportion  should  be 
about  fifty  yards  of  good  sand  to  twenty-five  barrels  of  lime, 
for  the  first  mixing,  which  should  be  thoroughly  done.  The 
hair  should  be  put  into  the  lime  before  mixing  in  the  sand. 
After  the  mortar  has  been  mixed  in  the  above  proportions 
for  ten  clays  or  more,  if  the  amount  of  materials  given  have 
been  used,  twenty-five  to  fifty  loads  of  sand  may  be  added 
and  worked  in.  It  is  said  that  the  water  that  rises  on  a 
bushel  of  slaked  lime,  and  where  plenty  of  water  has  been 
used,  if  removed  and  put  on  a  sharp  sand,  will  make  better 
stone  than  lime  and  sand  mixed,  showing  that  the  water 
should  be  retained  in  the  sand  and  lime  while  it  is  fresh,  and 
that  the  mortar  should  be  tempered  in  its  own  liquor.  Of 
course,  where  smaller  quantities  are  used,  the  proportion 
should  be  retained,  both  at  the  first  mixing  and  in  the  sand 
added  subsequently, 

A  pound  of  ten-p«nny  cut  nails  will  do  as  much  work  as 
two  pounds  of  wire  nails.  Taking  the  average  of  all  cut  nails, 
they  are  worth  nearly  double  as  much  as  wire  nails,  from 
tests  made  at  the  Watertown  Government  Arsenal. 


428 

COST  OF  EXCAVATING  AND  HANDLING  ROCK. 

The  average  weight  of  a  cubic  yard  of  sandstone  or  con- 
glomerate, in  place,  is  given  as  1.8  tons,  and  of  compact 
granite,  gneiss,  limestone  or  marble,  2  tons,  or  an  average  of 
1.9  tons,  or  4,256  pounds.  A  cubic  yard,  when  broken  up 
ready  for  removal,  increases  about  four-fifths  in  bulk,  and 
f~i  of  a  cubic  yard,  177  pounds,  is  a  wheelbarrow  load. 
Experience  shows  that,  with  wages  at  $i  per  day  of  10 
hours,  45  cents  per  cubic  yard  is  a  sufficient  allowance  for 
loosening  hard  rock.  Soft  shales  and  allied  rocks  may  be 
loosened  by  pick  and  plow  at  a  cost  of  20  cents  to  30  cents 
per  cubic  yard.  The  quarrying  of  ordinary  hard  rock  re- 
quires from  %  pound  to  ^  pound  and  sometimes  *4  pound 
of  powder  per  cubic  yard.  Drilling  with  a  churn  driller 
costs  from  12  to  iScenis  per  foot  of  hole  bored.  Upon 
these  data,  Mr.  Rigly  estimates  the  total  cost,  per  cubic 
yard  of  rock  in  place,  for  loosening  and  removing  by  wheel- 
barrow (labor  assumed  at  $i  per  day  of  10  hours),  as  fol- 
lows: When  distance  removed  is  25  feet,  total  cost=$o.  537; 
when  50  feet,  $0.549;  when  100  feet,  $0.573;  when  2OO<eet, 
$0.622;  when  500  feet,  $0.768;  when  1,000  feet,  $1.011;  and 
when  i, 800  feet,  $1.401.  This  is  exclusive  of  Contractor's 
profit.  ^ 

When  labor  is  $1.25  per  day,  add  25  per  cent,  to  the  cost 
prices  given;  when  $1.50  per  day,  add  50  per  cent,  and  so 
on.  In  hauling  by  cart,  the  cost  of  loading,  which  will  be 
about  8  cents  per  cubic  yard  of  rock  in  place,  and  the  addi- 
tional expense  of  maintaining  the  road  must  be  added. 
Allowing,  then,  851  pounds  as  a  cart-load,  the  total  cost  per 
cubic  yard  is  estimated,  when  removed  25  feet,  at  $0.596; 
when  50  feet,  $0.599;  when  100  feet,  $0.605;  when  200  feet, 
$0.617;  when  500  feet,  $0.655;  when  1,000  feet,  $0.717;  and 
when  j, 800  feet,  $0.94. 

IRON    BRICK. 

It  is  reported  that  the  German  Government  testing  labor- 
atory for  building  materials  has  reported  favorably  on  a  new 
paving-block  called  iron  brick.  This  brick  is  made  by  mix- 
ing equal  parts  of  finely-ground  clay,  and  adding  5  per  cent, 
of  iron  ore.  This  mixture  is  moistened  with  a  solution  of  25 
per  cent,  sulphate  of  iron,  to  which  fine  iron  ore  is  added 
until  it  shows  a  consistency  of  38  degrees  Baume.  It  is  then 
formed  in  a  press,  dried,  dipped  once  more  in  a  nearly  con- 
centrated solution  of  sulphate  of  iron  and  finely  ground  iron 
ore,  and  is  baked  in  an  oven  for  48  hours  in  an  oxidizing 
flame,  and  24  hours  in  a  reducing  flame- 


429 
DRY  ROT  IN  TIMBER. 

No  wood  which  is  liable  to  damp,  or  has  at  any  time 
absorbed  moisture,  and  is  in  contact  with  stagnant  air,  so 
that  the  moisture  cannot  evaporate,  can  be  considered  safe 
from  the  attack  of  dry  rot. 

Any  impervious  substance  applied  to  wood,  which  is  not 
thoroughly  dry,  tends  to  engender  decay ;  floors  covered 
with  kamptulicon  and  laid  over  brick  arching  before  the 
latter  was  dry  ;  cement  dado  to  wood  partition,  the  water 
expelled  from  dado  in  setting,  and  absorbed  by  the  wood, 
had  no  means  of  evaporation. 

Woodwork  coated  with  paint  or  tar  before  thoroughly 
dry  and  well  seasoned,  is  liable  to  decay,  as  the  moisture  is 
imprisoned. 

Skirtings  and  wall  paneling  very  subject  to  dry  rot,  and 
especially  window  backs,  for  the  space  between  woodwork 
and  the  wall  is  occupied  by  stagnant  air  ;  the  former  absorbs 
moisture  from  the  wall  (especially  if  it  has  been  fixed  before 
the  wall  was  dry  after  building),  and  the  paint  or  varnish 
prevents  the  moisture  from  evaporating  into  the  room. 
Skirting,  etc.,  thus  form  excellent  channels  for  the  spread  of 
the  fungus.  ^ 

Plaster  seems  to  be  sufficiently  porous  to  allow  the 
evaporation  of  water  through  it  ;  hence,  probably,  the  space 
between  ceiling  and  floor  is  not  so  frequently  attacked,  if 
also  the  floor  boards  do  not  fit  very  accurately  and  no  oil 
cloth  covers  the  floor. 

Plowed  and  tongue  floors  are  disadvantageous  in  cer- 
tain circumstances,  as  when  placed  over  a  space  occupied 
by  damp  air,  as  they  allow  no  air  to  pass  between  the  boards, 
and  so  dry  them. 

Beams  may  appear  sound  externally  and  be  rotten 
within,  for  the  outside,  being  in  contact  with  the  air, 
becomes  dryer  than  the  interior.  It  is  well,  therefore,  to 
saw  and  reverse  all  large  scantling. 

The  ends  of  all  timber,  and  especially  of  large  beams, 
should  be  free  (for  it  is  through  the  ends  that  moisture 
chiefly  evaporates).  They  should  on  no  account  be  imbed- 
ded in  mortar. 

Inferior  and  ill-seasoned  timber  is  evidently  to  be 
avoided.  * 

Whatever  insures  dampness  and  lack  of  evaporation  is 
conducive  to  dry-rot,  that  is  to  say,  dampness  arising  from 
the  soil ;  dampness  arising  from  walls,  especially  if  the 
damp-proof  course  has  been  omitted  ;  dampness  arising 


430 

from  use  of  salt  sand  ;  dampness  arising  from  drying  of  mor- 
tar and  cement. 

Stagnation  of  air  resulting  from  air  grids  get  ting  blocked 
with  dirt  or  being  purposely  blocked  through  ignorance. 
Stagnation  may  exist  under  a  floor  although  there  are  grids 
in  the  opposite  walls,  for  it  is  difficult  to  induce  the  air  to 
move  in  a  horizontal-  direction  without  some  special  means 
of  suction.  Corners  of  stagnant  air  are  to  be  guarded 
against. 

Darkness  assists  the  development  of  fungus ;  whatever 
increases  the  temperature  of  the  wood  and  stagnant  air 
(within  limits)  also  assists. 

PAINTING  FLOORS. 

Colors  containing  white  lead  are  injurious  to  wood  floors, 
rendering  them  softer,  and  more  liable  to  be  worn  away 
Paints  containing  mineral  colors  only,  without  white  lead, 
such  as  yellow  ochre,  sienna  or  Venetian  or  Indian  red,  have 
no  such  tendency  to  act  upon  the  floor,  and  may  be  used  with 
safety.  This  quite  agrees  with  the  practice  common  in  this 
country,  of  painting  floors  with  yellow  ochre  or  raw 
umber  or  sienna.  Although  these  colors  have  little  body, 
compared  with  the  white-lead  paint,  and  need  several  coals, 
they  form  an  excellent  and  very  durable  covering  for  the 
floor.  Where  a  floor  is  to  be  varnished,  it  is  found  that  var- 
nish made  by  drying  lead  salts  is  nearly  as  injurious  as  lead 
paint.  Instead  of  this,  the  borate  of  manganese  should  be 
used  to  dispose  the  varnish  to  dry,  and  a  recipe  for  a  good 
floor  varnish  is  given.  According  to  this,  two  pounds  of  pure 
white  borate  of  manganese,  pounded  very  fine,  are  to  be 
added,  little  by  little,  to  a  saucepan  containing  ten  pounds  of 
linseed  oil,  which  is  to  be  well  stirred,  and  gradually  raised  to 
a  temperature  of  three  hundred  and  sixty  degrees  Fahren- 
heit. Meanwhile,  heat  one  hundred  pounds  linseed  oil  in  a 
boiler  until  bubbles  form ;  then  add  to  it  slowly  the  first 
liquid,  increase  the  fire,  and  allow  the  whole  to  cook  for 
twenty  minutes,  and  finally  remove  from  the  fire,  and  filter 
while  warm  through  cotton  cloth  The  varnish  is  then 
ready,  and  can  be  used  immediately.  Two  coats  should  be 
used,  and  a  more  brilliant  surface  may  be  obtained  by  a  final 
coat  of  shellac. 


The  railroads  consume  half  of  the  coal  used  in  this  country. 


431 
COLD  WATER  SUPPLY  PIPES. 

The  following  matter,  in  catechetical  form,  illustrates 
the  teachings  of  the  New  York  Trades  Schools  in  this  con- 
nection : 

I. — What  size  should  the  pipe  from  the  street  main  to 
the  house  be  ? 

A. — The  supply  pipes  of  New  York  average  about  i  %  to 
i\4  inches  in  diameter. 

2. — What  material  is  used  for  this  pipe  in  New  York  ? 
K — Mostly  lead  pipes. 

3. —  r^hat  other  materials,  besides  lead,  are  used  for  sup- 
ply pipes  ? 

A. — Galvanized  iron,  ^rass,  and  tin-lined  lead  pipes. 

4. —  How  is  iron  used? 

A. — Plain,  galvanized,  and  linecc  ;nth  tin  or  glass. 

5. — What  are  the  advantages  and  disadvantages  of  lead 
pipes  ? 

A. — Advantages  are  its  ductility,  strength,  am*  easiness 
of  working,  also  its  durability.  Disadvantages  are  a^/.^er 
of  poisoning  the  water,  and  of  being  eaten  by  rats. 

6.  —  What  are  the  advantages  and  disadvantages  of  plain 
iron  pipe  ? 

A.  —Advantages  are  cheapness,  easiness  of  putting  to- 
gether, and  freedom  from  poisoning.  Disadvantages  are 
rusting,  and  filling  up  of  pipes. 

7.-  What  are  the  advantages  and  disadvantages  of  tin- 
lined  pipes  ? 

A.  —  Advantage  is  in  its  freedom  from  poisoning  water. 
Disadvantage  in  not  being  durable  for  hot -water  pipes. 

8. — What  are  the  advantages  and  disadvantages  of  glass- 
lined  pipe  ? 

A. —  Glass-lined  pipe  makes  an  excellent  water  pipe,  but 
is  liable  to  break  in  working  and  putting  up. 

9. — What  are  the  advantages  and  disadvantages  of  gal- 
vanized iron  pipe  ? 

A. — Galvanized  iron  pipe  is  cheap  and  free  from  rust, 
but  some  water  decomposes  zinc,  and  its  salts  are  poison- 
ous. 

10. — What  are  the  advantages  and  disadvantages  of 
brass  pipe? 

A. — When  brass  pipe  is  lined  with  tin  it  is  very  light 
and  strong;  but,  when  the  tin  wears  off,  there  is  danger  of 
poisoning  the  water. 

ii. — What  are  the  advantages  and  disadvantages  of 
block-tin  pipe? 


432 

A. — They  are  not  durable  for  hot  water,  and  are  very 
expensive. 

12. — What  are  the  advantages  and  disadvantages  of  tin- 
lined  lead  pipe  ? 

A. — They  are  not  durable. 

13. — In  using  tin-lined  lead  pipe,  what  must  be  guarded 
against? 

A. — The  lining  must  not  be  disturbed  or  the  tin  melted 
out.  " 

14. — How  should  the  supply  pipe  be  connected  with 
street  mains? 

A. — By  a  brass  tap  and  coupling. 

15. — How  should  a  lead  pipe  be  joined  to  an  iron  pipe? 

A. — By  a  brass  spud  or  soldering  nipple. 

16.— Should  the  supply  pipe  be*  so  arranged  that  it  can 
be  emptied?  and  why? 

A. — Yes.  To  prevent  freezing,  and  the  waterjfrom  stag- 
nating in  the  pipe. 

17. — What  precaution  can  be  taken  against  freezing  if 
the  main  is  within  three  feet  of  surface? 

A. — By  bending  the  pipe  a  few  feet  lower  at  the  main, 
and  continuing  the  pipe  at  the  lower  level. 

18. — In  crossing  an  area  with  a  supply  pipe,  what  precau- 
tion should  be  taken? 

A. — Cover  the  pipe  with  felt,  or  put  it  in  a  box  filled  with 
saw-dust,  to  prevent  freezing? 

19.  —  What  is  gained  by  putting  a  supply  pipe  from  street 
main  to  house  in  a  larger  iron  pipe? 

A. — The  air  in  a  larger  iron  pipe  protects  the  supply, 
and  steam  can  be  injected  to  thaw  pipe  if  it  freezes. 

20. — How  can  water  supply  be  increased  after  service 
pipe  enters  house? 

A. — The  flow  of  water  can  be  greatly  assisted  by  using  a 
larger  pipe  after  entering  the  house. 

21. — Is  there  any  way  to  arrange  a  pipe  so  that  drawing 
water  from  a  lower  floor  will  not  stop  or  retard  the  flow 
from  upper  floors  ? 

A. — The  best  way  would  be  to  proportion  branches  on 
different  floors  according  to  pressure  ;  the  smaller  the  press- 
ure the  larger  the  outlet. 

22. — Suppose  a  three-story  house  had  a  %  tap  from  main 
to  house,  and  connected  from  this  tap  to  top  of  boiler  with 
a.  1/4  inch  pipe ;  what  size  should  the  branch  pipes  to  base- 
ment fixtures  be  ? 

A. — One-half  to  five-eighths  should  be  large  enough. 

23. — The   parlor  floor   contains  a  pantry  sink,  a  wash- 


433 

basin  and  a  water-closet  ;  how  large  should  the  supply  pipe 
from  basement  to  parlor  floor  be  ? 

A. — About  I  inch  in  diameter. 

24. — How  large  the  branch  pipes  to  fixtures  ? 

A.      l/z  to  y%  in  diameter, 

25. — The  second  floor  contains  a  bath,  two  Avater-closcts 
and  five  wash-basins  ;  how  large  should  the  pipe  from  par- 
lor to  second  floor  be  ? 

A. — About  I  inch  in  diameter. 

26. — How  large  should  the  pipe  from  basement  t<.  tank 
be? 

A. — About  i%  hich  in  diameter. 

27. — In  a  building  of  six  or  more  stories  in  height  \vifcN 
cold  water  supply  drawn  from  tank  on  upper  r,oors,  dj.as 
any  difficulty  occur  ? 

A. — Yes.     On  the  lower  floors  the  pressure  i :  too  gresj. 

28. — How  can  it  be  remedied  ? 

A. — By  diminishing  branch  pipes  to  give  a  y-roportional 
supply. 

29. — Can  supply  pipe  be  so  arranged  tha>  water  can  be 
drawn  from  the  main  or  from  tank? 

A. — Yes.  By  using  a  special  stop-co'\  for  the  pur- 
pose. 

30. — What  precautions  should  be  tak</  .  to  prevent  pipes 
freezing  ? 

A. — By  placing  as  far  from  frost  as  possible,  and  by 
proper  boxing  and  felting. 

31. — Why  are  pipes  liable  to  burst  when  they  freeze  ? 

A. — The  expansion  expands  the  pipes,  and,  consequently, 
they  burst. 

32. — What  is  the  expanding  pressure  of  freezing  water  ? 

A. — Thirty  thousand  pounds  to  the  square  inch. 

33. — What  means  are  taken  to  thaw  out  a  service-pipe  ? 

A. — The  application  of  heat  externally  or  steam  and  hot 
water  internally  is  about  the  best  means. 

34.— Is  the  external  application  of  heat  objectionable 
with  iron  pipes  ? 

A. — 'Yes  ;  as  the  sudden  contraction  is  as  dangerous  as 
the  expansion. 

35. — In  carrying  supply  pipes  across  a  floor,  what  pre- 
caution can  be  taken  to  protect  ceiling  below  from  a  leak  ? 

A. — By  putting  pipes  in  a  box  lined  with  lead,  and  hav- 
ing a  waste,  or  tell-tale,  pipe  at  lowest  point. 

36.  —  Does  fresh  mortar  injure  lead  pipes  ? 

A. — As  the  lime  in  fresh  mortar  is  corrosive  and  forms  a 
soluble  compound,  it  is  an  injury  to  lead  pipes. 


434 
PRESSURES  ON  TANKS. 

Q. — In  a  full  cubical  tank,  what  is  the  pressure  on  any 
Vertical  side  ? 

A.  — One-half  the  weight  of  the  contents. 

Q.' — In  a  full  conical  vessel  standing  on  its  base,  what  is 
the  pressure  on  the  tmse  ? 

A. — Three  times  the  we?gLt  rf  the  contents. 

Q. — In  a  hollow  sphere,  full  of  liquitr,  \Vrt^:  *  ixe  press- 
ure on  the  surface  of  the  lower  half  ? 

A. — Three  times  the  weight  of  contents. 

TINNING  BY  SIMPLE  IMMERSION. 

Argentine  is  a  name  given  to  tin  precipitated  by  gal- 
vanic action  from  its  solution.  This  material  is  usually  ob- 
tained by  immersing  plates  of  zinc  in  a  solution  of  tin,  con- 
taining 6  grammes  (about  90  grains)  of  the  metal  to  the  litre 
(0.88).  In  this  way  tin  scrap  can  be  utilized.  To  apply  the 
argentine  according  to  M.  P.  Marino's  process,  a  bath  is 
prepared  from  argentine  and  acid  tart  rate  of  potash,  ren- 
dered soluble  by  boric  acid.  Pyrophosphate  of  soda,  chlo- 
ride of  ammonium,  or  caustic  soda  may  be  substituted  for  the 
acid  tartrate.  The  bath  being  prepared,  the  objects  to  be 
coated  are  plunged  therein,  first  having  been  suitably  pickled 
and  scoured,  and  they  may  be  subjected  to  the  action  of  an 
electric  current.  But  a  simple  immersion  is  enough.  The 
bath  for  this  must  be  brought  to  ebullition,  and  the  objects 
of  copper  or  brass,  or  coated  therewith,  may  be  immersed 
in  it. 

HOW  TO  FIND  THE  AMOUNT  OF  STEAM-PIPE 
REQUIRED  TO  HEAT  A  BUILDING  WITH 
STEAM. 

Rule  for  rinding  the  superficial  feet  of  steam-pipe  required 
to  heat  any  building  with  steam  :  One  superficial  foot  of 
steam-pipe  to  six  superficial  feet  of  glass  in  the  windows,  or 
one  superficial  foot  of  steam-pipe  for  every  hundred  square 
feet  of  wall,  roof  or  ceiling,  or  one  square  foot  of  steam-pipe 
to  eighty  cubic  feet  of  space.  One  cubic  foot  of  boiler  is 
required  for  every  fifteen  hundrtd  cubic  feet  of  space  to  be 
warmed.  One  horse-power  boiler  is  sufficient  for  forty 
thousand  cubic  feet  of  space  Five  cubic  feet  of  steam,  at 
seventy-five  pounds  pressure  to  the  sanare  inch,  w«»iohs  one 
pound  avoinl'"^" 


435 

SEASONING  TIMBER. 

Timber,  when  freshly  cut,  contains -from  thirty-seven  to 
forty-eight  per  cent,  of  water,  the  kind,  the  age,  and  the 
season  of  vegetation  go  /e"iing  the  percentage.  Older  i/ood 
is  generally  heavier  thai  young  wood,  and  the  weight  of 
wood  cut  in  the  active  season  is  greater  than  that  of  wood 
cut  in  the  dormant  season.  Water  in  wood  is  not  chemically 
combined  with  the  fib*  -,  and,  when  exposed  to  the  atmos- 
phere, the  moisture  evaj  orates.  The  wood  becomes  lighter 
until  a  certain  point  is  reached  in  the  drying-out  process, 
after  which  it  gains  or  loses  in  the  weight  according  to  the 
variations  in  the  moisture  and  temperature  of  the  atmos- 
phere. Following  is  a  table  showing  the  percentage  in 
weight  of  water  in  round  woods  from  young  trees  at  different 
lengths  of  time  after  cutting  : 
Kind  of  Wood.  6  mos.  ^  12  mos.  18  nios.  2411105. 

Beech 30.44  23.46  18.60  19-9S 

Oak 32.71  26.74  2o-25  20.28 

Hornbeam 27.19  23.08  20.00  J8-59 

Birch 39.72  29.01  22.73  19.52 

Poplar 40.45  26.22  17.77  I7«92 

Fir 33.78  16.87  15.21  18.00 

Pine 41.70  18.67  15.^3  17.42 

According  to  these  figures,  taken  from  actual  trials,  there 
is  nothing  gained  by  keeping  wood  longer  than  eighteen 
months,  so  far  as  drying  or  seasoning  is  concerned.  In  the 
woods  mentioned,  there  appears  to  be  an  actual  loss  in 
some,  and  only  a  slow  gain  in  others  after  that  length  of 
time.  The  pine,  fir,  and  beech  gained  moisture,  and  the 
others  in  the  list  lost  only  very  slightly  after  the  eighteen 
months  had  passed. 

PROPOSED  GREAT  ENGINEERING  FEAT. 
A  gigantic  scheme  has  been  proposed,  by  which  the  can- 
ons of  the  Rocky  Mountains  are  to  be  dammed  up  from  the 
Canadian  boundary  to  Mexico,  in  order  to  form  vast  reser- 
voirs of  water  to  be  used  in  the  irrigation  of  arid  lands,  and  so 
prevent  floods  in  the  lower  Mississippi.  Major  Powell,  direc- 
tor of  the  national  survey,  estimates  that  at  least  150,000 
square  miles  of  land  might  thus  be  reclaimed  —  a  territory 
exceeding  in  extent  one-half  of  the  land  now  cultivated  in  the 
United  States.  The  plan  is  to  build  dams  across  all  the  can- 
ons in  the  mountains  large  enough  and  strong  enough  to  hold 
back  the  floods  from  heavy  rains  and  melting  snows,  and  then 
let  the  water  down  as  it  may  be  needed  upon  the  land  to  be 
reclaimed. 


436 
oN  THE  USE  OF  GLUE. 

In  order  to  use  gl.w*  successfully,  says  a  writer  of  experi- 
ence, a  great  deal  of  ^vnerience  is  required,  and  it  is  useless 
for  the  amateur  to  try  K '  j  he  will  only  spoil  the  work.  So, 
unless  the  workman  is\\^H  experienced  in  the  treatment 
and  the  application  of  the  ftlue,  he  had  better  leave  it  alone 
entirely.  To  render'  the  op  Cation  successful,  two  consider- 
ations must  be  taken  into  account:  First,  to  do  good  glu- 
ing requires  that  the  timber  be  well  seasoned  and  thoroughly 
ar  /,  taking  care  that  the  joints  to  be  glued  are  well  fitted. 
'jo^t^-.!1.  hi  preparing  the  parts  to  be  glued,  each  piece  should 
be  scratched  with  a  sharp  file  or  piece  of  a  fine  saw,  to 
make  the  glue  hold  better.  The  shop  should  be  kept  at  a 
proper  temperature,  and  the  material  heated  so  that  the 
glue  may  flow  quite  freely.  Having  the  glue  properly  pre- 
pared, spread  it  evenly  upon  the  parts  so  as  to  fill  up  the 
pores  and  grain  of  the  wood,  then  put  the  pieces  together 
as  rapidly  as  possible,  using  clamps  and  thumb-screws  to 
draw  the  joints  tightly  together  ;  all  superfluous  glue  should 
be  washed  off,  taking  great  care  not  to  use  too  much  water, 
or  allowing  any  to  remain  on  the  pieces  put  together.  The 
greatest  cause  of  bad  gluing  is  in  using  inferior  glue  and 
in  laying  it  on  unevenly.  Before  using  a  new  brand  of  glue 
it  is  safer  to  test  it  by  gluing  a  piece  of  whitewood  and 
ash  together,  clamping  it  with  a  thumb-screw,  and,  when 
dry,  insert  a  chisel  where  it  is  put  together,  and,  if  the  joint 
separates  where  it  is  glued,  it  is  not  fit  to  use,  and  should  be 
rejected  at  once.  The  wood  should  split  or  give  way  rather 
than  the  substance  promoting  adhesion.  This  is  a  practi- 
cal and  severe  test,  but  it  will  pay  to  apply  it,  in  the  sta- 
bility of  the  work. 

GLUE  PAINT  FOR  KITCHEN  FLOOR. 

For  a  kitchen  floor,  especially  one  that  is  rough  and 
uneven,  the  following  glue  paint  is  recommended  :  To  three 
pounds  of  spruce  yellow  add  one  pound,  or  two  pounds  if 
desired,  of  dry  white  lead,  and  mix  well  together.  Dissolve 
two  ounces  of  glue  in  one  quart  of  water,  stirring  often  until 
smooth  and  nearly  boiling.  Thicken  the  glue  water  after  the 
manner  of  mush,  nntil  it  will  spread  smoothly  upon  the  floor. 
Use  a  common  paint  brush  and  apply  hot.  This  will  fill  all 
crevices  of  a  rough  floor.  It  will  dry  soon,  and  when  dry 
apply  boiled  linseed  oil  with  a  clean  brush.  In  a  few  hours 
it  will  be  found  dry  enough  to  use  by  laying  papers  or  mats  to 
step  on  for  a  few  days.  WJ'  *n  it  needs  cleaning,  use  hot  suds. 


EFFECT    OF    THE    ATMOSPHERE    ON   BRICKS. 

Atmospheric  i  lilaence  upon  bricks,  tiles  and  other  build- 
ing materials  obtained  by  the  burning  of  plastic  clays, 
depends  very  much  on  the  chemical  composition  of  the 
clays  and  on  the  degree  of  burning.  Thus,  any  distinct  por- 
tions of  limestone  present  in  them  would  be  converted 
into  quicklime  in  the  kiln,  and,  when  the  bricks  were  thor- 
oughly wetted,  would  expand  in  such  a  manner  as  to  disin- 
tegrate the  mass.  If  the  clay  used  is  too  poor  —  that  is  to 
say,  if  it  contains  an  excess  of  sand — the  bricks  will  not 
become  sufficiently  fused,  ar.d.  upon  exposure  to  the  weather, 
their  constituent  parts  will  separate.  It  is  t.>  be  ob-erved 
that  in  bricks,  as  in  stones,  decomposition  does  not  take 
•place  \vith  the  greatest  rapidity  where  constant  moisture 
exists,  but  rather  where,  from  the  absence  of  capillarity, 
variable  according  to  the  moisture  furnished  by  the  atmos- 
phere, either  directly  or  indirectly,  a  series  of  alternatic^a 
of  dryness  and  humidity  prevail. 

Th»  foundation  walls  of  buildings  do  noi  in  fact  suffer  so 
much  in  the  parts  immediately  upon  the  ground  as  they  do 
in  those  at  a  height  of  from  one  to  three  feet,  according  to  the 
permeability  of  the  materials  employed.  When  bricks 
made  of  clay  containing  free  silica  are  laid  in  mortar,  and 
moisture  can  pass  freely  from  either  one  or  the  other,  it 
may  be  observed  that  the  edges  in  contact  become  harder 
than  the  body  of  the  bricks.  No  doubt  this  arises  from 
the  formation  of  a  silicate  of  lime  and  alumina,  the  lime 
being  furnished  by  the  passage  of  the  water  through  the  bed 
of  the  mortar. 

THE  GREAT  EIFFEL  TOWER. 
Oneof  the  principal  features  of  interest  at  the  Paris  Ex- 
position  is  the  Eiffel  tower.  It  is  constructed  of  iron,  and  rises 
^~  ft  height  of  984  feet.  As  the  greatest  height  yet  reached 
in  any  structure  is  that  of  the  Washington  monument,  550 
feet,  some  idea  can  be  formed  of  the  great  distance  upward 
that  this  tower  will  go.  This  tower  weighs  7,000  tons,  and 
cost  4,500,000  francs.  One  object  of  its  construction  is  to 
light  the  Exposition  grounds.  The  tower  will  be  supplied 
with  elevators,  which  will  land  passengers  971  feet  from  the 
earth.  There  is  talk  of  supplying  it  with  electric  lights  of 
19,000,000  candle  power.  Four  such  towers,  with  a  capacity 
of  50,000,000  each,  it  is  thought,  would  light  the  whole  city 
of  Paris.  Perhaps  this  tower  will  decide  the  question 
whether  or  not  it  is  possible  to  light  an  entire  city  from  a 
few  points,  if  not  from  one. 


43* 
ROT  IN  TIMBER. 

The  principal  cause  of  the  lack  of  proper  durability  of 
timber  in  buildings  is  the  porosity  of  the  lumber  used  and 
the  consequent  liability  to  absorb  moisture.  Coarse-grained 
woods  of  quick  growth  are  more  liable  to  this  defect  than 
those  of  tough  fiber  and  slow  growth.  When  timber  be- 
comes repeatedly  wet  and  dry,  it  becomes  brittle  and  weak- 
ened, or  "  its  nature  is  gone,"  as  the  workmen  say.  Rot  is 
of  two  kinds,  wet  and  dry,  and  moisture  .  is  the  essential 
element  in  both  cases,  the  only  difference  being  that  in  the 
first  the  moisture  is  Quickly  evaporated  by  exposure  to  the 
air,  and  in  the  latter,  when  there  is  no  exposure,  it  produces 
a  species  of  fungus  and  minute  worms  which  eat  in  between 
the  fibers,  and  gradually  produce  disintegration.  Sap  wood 
is  more  perishable  than  heart  wood,  for  the  former  contains 
more  of  the  saccharine,  principle,  and  renders  the  wood  liable 
to  a  fermentive  action. 

The  prevalent  practice  of  confining  unseasoned  timber  by 
building  it  close  into  walls,  thus  preventing  the  ready  evap- 
oration of  whatever  moisture  happens  to  get  to  it,  is  a  bad 
one.  The  ends  of  the  wood,  especially,  should  be  sur- 
rounded by  an  open-air  space,  however.small,  as  it  is  the  ends 
where  the  dampness  is  most  liable  to  penetrate  into  the 
structure  of  the  wood.  It  is  a  well-known  fact  that  a  log  of 
green  timber,  when  kept  immersed,  will  become  water-logged 
and  sink,  and,  of  course,  become  unfit  for  use  afterward. 
The  same  process,  only  slower,  applies  when  it  is  exposed 
to  damp  with  no  facilities  for  rapid  evaporation.  Quick- 
lime, when  assisted  by  moisture,  is  a  powerful  aid  in  hasten- 
ing decomposition,  in  consequence  of  its  affinity  for  carbon. 
Miid  lime  has  not  this  effect,  but  mortar,  as  used  in  build- 
ings, requires  a  considerable  length  of  time  to  become  inert 
in  its  action  as  a  corroding  agent ;  therefore  bedding  timber 
in  damp  mortar  is  very  injurious,  and  often  the  cause  of  un- 
accountable decay.  Wood,  in  a  dry  state,  does  not  seem  to 
be  injured  by  contact  with  dry  lime,  it  being  rather  a  preser- 
vative. An  example  of  this  is  shown  in  lathing  covered  with 
plaster,  which  often  retains  its  original  strength  when  sur- 
rounding timbers  are  completely  rotted  away. 

Anything  that  will  hinder  the  absorbing  process  will  ex- 
tend the  life  of  a  wood,  such  as  a  coating  of  tar,  paint,  or  a 
charring  of  the  surface.  The  latter  method  will  prove  the 
most  effective,  if  sufficiently  deep,  as  the  charred  coating  is 
practically  indestructible,  closes  the  pores  of  the  wood,  and 
will  prevent  the  bursting  into  flame  in  case  of  a  fire.  If  all 


439 


joists,  girders  and  inside  beams  of  every  kind  were  treated 
to  a  superficial  charring  process,  it  would  tend,  in  conjuno 
tion  with  fire-proof  paint  applied  to  outside  finishing  work, 
to  make  a  building  as  nearly  fire-proof  as  wood  in  any  con- 
dition will  allow. 


NUMBER   OF    BRICKS   REQUIRED   TO 
CONSTRUCT  A  BUILDING. 


Superficial 
feet  of 
Wall. 

Number  of  Bricks  to  Thickness  of 

4  Inch 

8  Inch 

12  Inch 

i  6  Inch 

2O  Inch 

24  Inch 

i  

2  

3  

7 
15 

23 
30 

38 
45 

§ 

68 
75 
IS° 
225 
300 
375 
45° 
525 
600 

675 
750 
1,500 
2,250 
3,000 

15 

30 

45 

5? 

75 
90 

I05 

120 
135 

15° 
300 

45° 
600 

75° 

QOO 
I,O5O 

1,200 
1,350 
1,500 
3,OOO 
4,500 
6,OOO 

22 

45 
68 
90 

"3 

i35 
158 
i  So 
203 
225 
45o 
<-75 
900 
1,125 
i?35o 

1.575 

i,  800 

2,025 
2,250 
4,500 
6,75o 
9,000 

29           37 
60           75 
90         113 

120             150 

150          1  88 
1  80!         225 

2IO              263 

240          300 

270       338 

300         375 
600         750 
900      1,125 

1,2OO;        I,5OO 
1,5OO         1,875 
I,  §00        2,250 
2,  IOO         2,625 
2,4OO        3,OOO 
2,/Oo!        3.375 

3,000      3,750 
6,000      7,500 
9,000     11,250 
12,000!    15,000 

45 
90 

& 

22$ 
270 

315 
360 

405 
450 
900 
1.350 
1,  800 
2,250 
2,700 
3>I50 
3,600 
4,050 
4,500 
9,OOO 
13>500 
l8,OOO 

A 

t 

I::;:::: 

7  

8  

9 

10  .  . 

20  
30  

40 

50  

60.  .. 

70  ..    .    . 

80  ... 

QO    . 

IOO 

2OO  

3OO  

4OO  

Sycamore  is  being  introduced  quite  extensively  for  interior 

finish.      When  properly  selected  it  makes  a  very  handsome 
finish.     Care  should  be  taken  in  securing  it,  rs  it  is  nearly  as 
bad  to  warp  as  elm.      It   should  be  well  backed    with    P'r 
spruce  or  hemlock. 


440 
FIRE-PROOFING    WOODWORK. 

A  door  of  the  right  construction  to  resist  fire  should  be 
made  of  good  pine,  and  should  be  of  two  or  more  thicknesses 
of  matched  boards  nailed  across  each  other,  either  at  right 
angles  or  at  forty-five  degrees.  If  the  doorway  be  more 
than  seven  feet  by  four  feet,  it  would  be  better  to  use  three 
thicknesses  of  same  stuff;  in  other  words,  the  door  should 
be  of  a  thickness  proportioned  to  its  area.  Such  a  door 
should  always  be  made  to  shut  into  a  rabbet,  or  flush  with 
the  wall  when  practicable  ;  or,  if  it  is  a  slide  door,  then  it 
should  be  made  to  shut  into  or  behind  a  jamb,  which  would 
press  it  up  against  the  wall.  Both  sides  of  the  door  and  its 
jambs,  if  of  wood,  should  then  be  sheathed  with  tin,  the 
plates  being  locked  at  joints,  and  securely  nailed  under  the 
locking  with  nails  at  least  one  inch  long.  No  air  spaces 
should  be  left  in  a  door  by  paneling  or  otherwise,  as  the  door 
will  resist  best  that  has  the  most  solid  material  i:i  it.  In 
most  places  it  is  much  better  to  fit  the  door  upon  inclined 
metal  sliders  than  upon  hinges. 

*5  This  kind  of  door  miy  b  2  fitted  with  automatic  appliances, 
so  that  it  will  close  of  itself  when  subjected  to  the  heat  of  a 
fire  ;  but  these  appliances  do  not  interfere  with  the  ordinary 
methods  of  opening  and  shutting  the  door.  They  only 
constitute  a  safegard  against  negligence.  The  construction 
of  shutters  varies  from  that  of  doors  only  in  the  use  of 
thinner  wood. 

Under  this  heading  may  be  classed  all  the  doors  of  iron, 
whether  sheet,  plate,  cast  or  rolled,  single,  double  or  hollow, 
plain  or  corrugated,  none  of  which  are  capable  of  resisting 
fire  for  any  length  of  time  ;  also  wooden  doors  covered  with 
tin  on  one  side  only,  or  covered  with  zinc,  which  melts  at 
700  degrees  Fahrenheit, 

The  wooden  door  covered  with  tin  only  serves  its  pur- 
pose when  the  wood  is  wholly  encased  in  tin,  put  on  in  such 
a  way  that  no  air,  or  the  minimum  of  air,  can  reach  the 
wood  when  it  is  exposed  to  the  heat  of  a  fire.  Under  these 
conditions,  the  surface  of  the  wood  is  converted  into  char- 
coal ;  charcoal  being  a  non-conductor  of  heat,  itself  tends  to 
retard  the  further  combustion  of  the  wood.  But,  if  air 
penetrates  the  tin  casing  in  any  measure,  the  charcoal  first 
made,  and  then  the  wood  itself,  are  both  consumed,  and  the 
door  is  destroyed.  In  like  manner,  if  a  door  is  tinned  only 
only  on  one  side,  as  soon  as  the  heat  suffices  to  convert  the 
surface  of  the  wood  under  the  tin  and  next  to  the  fire  into 
charcoal,  the  oxygen  reaches  it  from  the  outside,  and  the 
door  is  ef  little  more  value  than  a  thin  door  of  iron,  or  plain 

•  " 


441 

DIMENSIONS    OF    THE    MOST    IMPORTANT    OF 
THE  GRE-AT  CATHEDRALS. 

Length,         Breadth,  Height, 

feet.  feet.  feet. 

St.  Peter's 613  450  438 

St.  Paul's 500  248  404 

Duomo 555  240  375 

Notre  Dame 416  153  298 

Cologne 444  283 

Toledo 395  178  ... 

Rheinu.; 480  163  117 

Rouen 469  146  465 

Chartres 430  150  373 

Antwerp 384  171  402 

Strasbourg 525  195  465 

Milan 477  186  360 

Canterbury 530  154  235 

York 524  261 

Winchester 554  208 

Durham 411  170  214 

Ely-. 617          .78 

Salisbury 473  229  279 

SUGGESTIONS  FOR  COLORS. 

In  forms,  tints,  and  colors  the  ocean  depths  supply  valu- 
able decorative  suggestions.  On  silverware  the  iridescent 
hues  of  tropical  shells  are  skillfully  reproduced,  and  on 
ceramic  ware  their  fascinating  combinations  of  tints  and  the 
gradations  of  these  shells  have  been  too  much  hidden  away  in 
cabinets,  instead  of  being  studied  by  designers  for  their  ele- 
gant curvatures  and  attractive  colors.  The  delicate -and 
varied  hues  of  the  sea  anemone,  and  the  curves,  volutes  and 
flowing  lines  of  the  univalves  and  bivalves  are  worthy  of 
patient  stud/  with  reference  to  graceful  and  fanciful  orna- 
mentation. 

REMOVAL  OF  OLD  VARNISH. 
A  Mr.  Myer  has  just  patented,  in  Germany,  a  composi- 
tion for  removing  old  varnish  from  objects.  It  is  obtained 
by  mixing  five  parts  of  36  per  cent,  silicate  of  potash,  one  of 
40  per  cent,  soda  lye,  and  one  of  sal  ammoniac  (hydrochlor- 
ate  of  ammonia). 


442 
DECIMAL  EQUIVALENTS  OF  INCHES,  FEET  AND  YARDS. 


Frac 

Dec. 

Dec. 

In 

Feet. 

Yds. 

of  an 

of  an 

of  a 

= 

•0833  = 

.0277 

Inch. 

Inch. 

Foot. 

2 

= 

.1666  = 

•°555 

1-16 

= 

.0625  = 

.00521 

3 

= 

•25   = 

.0833 

1A 

= 

.125  = 

.01041 

4 

= 

•33^3  == 

.mi 

3-i6 

= 

•1875  = 

.01562 

5 

= 

.4166  = 

.1389 

X 

= 

.25   = 

.02083 

6 

= 

•5   = 

.1666 

5-i6 

= 

•3125  = 

.02604 

7 

S3* 

•5833  — 

.1944 

y* 

= 

•375  = 

•03125 

8 

= 

.666  = 

.2222 

7-16 

= 

•4375  = 

•03645 

9 

= 

•75   == 

•25 

» 

= 

•5 

.04166 

10 

= 

•8333  = 

.2778 

9-16 

= 

•5625  = 

04688 

ii 

= 

.9166  == 

•3055 

# 

= 

.625  = 

.05208 

12 

= 

i.   = 

•3333 

11-16 

= 

.6875  = 

.05729 

* 

= 

•75   = 

.06250 

13-16 

= 

.8125  = 

.06771 

g 

= 

•8/5  = 

.07291 

DECIMAL  EQUIVALENTS  OF  OUNCES  AND  POUNDS. 


Oz. 

Lb>. 

Oz. 

Lbs.    [ 

Oz. 

Lbs. 

l/4  = 

.015625 

4   = 

•25 

8l/2 

=  -5313 

y*  = 

•03125 

4K  = 

.2813 

9 

=  -S625 

H  = 

.046875 

5   - 

•3!25 

IO 

==•625 

.0625 

5K  = 

•3438 

II 

=  .6875 

i^  = 

•09375 

6   = 

•375 

12 

=  -75 

2   = 

.125 

6%  == 

.4063 

13 

=  -8125 

2*/2  = 

.15625 

7   = 

•4375 

H 

=  .875 

3  = 

.1875 

7K  = 

.4688 

15 

=  -9375 

3^  = 

.21875 

8  = 

•5     ! 

16 

1ECTS. 

A  person  following  the  occupation  of  forming  plans,  draw- 
ings and  specifications  for  building  purposes,  representing 
himself  as  an  architect,  is  presumed  in  law  not  only  as  being 
such,  but  to  be  learned  in  the  profession. 

If  there  is  any  obscurity  in  the  drawings  and  specifications, 
the  contractor  should  apply  to  the  architect  for  directions,  or 
be  liable  for  the  consequences. 

There  is  no  fixed  rule  as  to  compensation  of  architects  in 
the  United  States  law. 

The  architect's  contract  does  not  survive  to  his  represent- 
ative. So,  if  there  is  a  contract  to  complete  certain  work 


443 

for  a  certain  sum,  the  representative  of  a  deceus  ..'; 
cannot  recover  for  the  part  performance. 

In  Competitions  it  should  always  be  made  clearly  under- 
stood that  the  drawings,  etc.,  are  subject  to  approval,  for 
otherwise  the  party  receiving  them  will  be  liable  fir  their 
value,  whether  used  or  not. 

An  architect  has  not  the  right  to  substitute  another  per- 
son in  h's  stead. 

If  the  architect  frau  lulently  or  capriciously  ie"uses  t->  give 
proper  certificates  when  required,  the  buiVIer  may  maintain 
an  action  for  specific  performance  or  against  the  architect  for 
damages. 

PRESERVATION  OK  WOOD   l;V   L1MK. 

I  have  for  many  years  bee  i  in  the  habit  of  preparing 
home-grown  timber  of  the  inferior  sort  of  fir  —  Scotch  spruce 
and  silver  —  by  sfeeping  it  in  a  tank  (that  is,  a  ho'ed'igin 
clay  or  peat,  which  was  fairly  water  tight)  MI  a  satura'ed  s  >Iu- 
tion  of  lime.  Its  effect  on  the  sap- WOOL:  is  to  s->  )  a.'-den  it 
and  fill  it  with  pores  that  it  perfectly  resists  the  attacl.s  of  the 
little  wood-boring  beetle,  and  makes  it,  in  fact,  e-]ua'!y  as  dura- 
ble as  the  made  wood.  I  had  a  mill  which  was  lofted  with 
Scotch  fir  prepared  in  this  way  in  1850,  and  it  is  in  perrect 
preservation.  The  timber  is  packed  as  closely  as  it  will  lie  in  the 
tank,  water  is  let  in,  and  unslacked  lime  is  thrown  on  the  top 
and  well  stirred  about.  There  is  no  danger  that  the  solution 
Will  not  find  its  way  to  everything  in  the  tank.  I  leave  the 
wood  in  the  solution  for  two  or  three  months,  by  the  <  n  I  of 
which  time  an  inch  board  will  be  fully  permeated  by  it.  Joists 
and  beams  would,  of  course,  take  a  longer  time  for  saturation  ; 
but,  in  practice,  we  find  that  the  protection  afforded  by  two 
or  three  months'  steeping  is  sufficient,  if  the  scantlings  are  cut 
to  the  sizes  at  which  they  are  to  be  used. 

A  VERY  DURABLE  WOOD. 

The  interesting  fact  is  stated  that  so  indestructible  by 
wear  or  decay  is  the  African  teak  wood  that  vessels  built  of  it 
have  lasted  one  hundred  years,  to  be  then  only  broken  up 
because  of  their  poor  sailing  qualities  from  faulty  models. 
The  wood,  in  fact,  is  one  of  the  most  remarkable  known,  or 
account  of  its  very  great  weight,  hardness  and  durability,  its 
weight  varying  from  forty-two  to  fifty-two  pounds  per  cubic 
foot.  It  works  easily,  but,  on  account  of  the  larue  quantity 
of  silex  contained  in  it,  the  tools  employed  are  quickly  worn 
away.  It  also  contains  oil,  which  prevents  spikes  and  other 
iron  work,  with  which  it  comes  in  contact,  from  rusting. 


444 
HOW  TO   BUILD  AN  ICE  HOUSE. 

I.  The  ice  house  floor  should  be  above  the  level  of  the 
ground,  or,  at  least,  should  be  above  some  neighboring  area 
to  give  an  outfall  for  a  drain,  put  in  such  a  way  as  to  keep 
the  floor  clear  of  standing  water. 

2.  The  walls  should  b,?  hollow.  A  four  inch  lining-wall, 
tied  to  the  outer  wall  with  hoop  iron,  and  with  a  three-inch 
air  space,  would  answer  ;  but  it  would  be  better,  if  the  air 
space  is  thoroughly  drained,  to  fill  it  with  mineral  wool,  or 
some  similar  substance,  to  prevent  the  movement  of  the  air 
entangled  in  the  fibers,  and  thus  check  the  transference  by 
convection  of  heat  from  the  outside  of  the  lining  wall. 

3.  A  roof  of  thick  p'ank  will  keep  out  heat  far  better 
than  one  of  thin  boards  with  an  air  space  under  it. 

4.  Shingles  will  be  much  better  for  roofing  than  slate. 

5-  It  is  best  to  ventilate  the  upper  portion  of  the  build- 
ing. If  no  ventilation  is  provided,  the  confined  air  under 
the  roof  becomes  intensely  heated  in  summer  ;  and  outlets 
should  be  provided,  at  the  highest  part,  with  inlets  at  con- 
venient points,  to  keep  the  temperature  of  the  air  ove*'  the 
ice  at  least  down  to  that  of  the  exterior  atmosphere. 

TESTING  EXTERIOR  STAINS. 

Since  the  use  of  stains  for  exterior  work  became  so  gen- 
eral, several  stains,  some  good  and  some  bad,  have  appeared 
on  the  market,  so  that  a  few  points  on  estimating  their  com- 
parative values  may  not  be  amiss. 

The  nose,  and,  to  a  less  degree,  the  eye,  are  admirable 
allies  for  this  work,  but,  unassisted,  are  not  infallible.  The 
following  is  about  the  simplest  method  of  testing  : 

1.  Search  for  kerosene  by  warming,  and  then  noting  the 
smell.     Als  >,  note  the  thinness1  and  lack  of  covering  power 
which  kerosene  causes.     Kerosene  is  simply  a  cheapener. 

2.  See   how   fine   it    brushes   out  on   a  smooth  shingle. 
There  should  not  be  the  slightest  grit  or  any  perceptible 
grains  of  pigment,  the  presence  of  which  will  prove  that  the 
coloring  was  mixed  dry  with   the   vehicle,   and  w^as  never 
ground  fine. 

3-  Pour  out  some  of  the  stain  in  a  tumbler.  If  it  begins 
to  settle  at  once,  except  in  the  case  of  a  chrome  yellow  or 
/green,  it  is  made  r.s  above  stated,  by  mixing  a  dry  paint  with 
the  vehicle,  and  therefore  should  be  avoided. 

A  well-ground  oil  stain  tested  in  this  way  held  up  a  whole 
day,  and  a  creosote  stain  a  day  and  a  half. 

Of  course,  when  debating  between  two  stains,  it  is  best 


445 

to  try  them  side  by  side.  In  such  case  the  comparative  color- 
strength  may  be  determined  by  diluting  equal  quantities  of 
both  stains  at  about  the  same  shade,  with  equal  quantities  of 
turpentine,  and  then  applying  the  diluted  colors  to  wood,  and 
noting  the  depth  of  the  color.  One  part  of  stain  to  ten  parts 
of  turpentine  is  a  good  strength. 

HOW  TO  PREPARE  CALCIMINE 

Soak  one  pound  of  white  glue  over  night;  then  dissolve 
it  in  boiling  water,  and  add  twenty  pounds  of  Paris  white, 
diluting  with  water  until  the  mixture  is  of  the  consistency 
of  rich  milk.  To  this  anv  tint  can  be  given  that  is  de- 
sired. 

Lilac  —  Add  to  the  calcimine  two  parts  of  Prussian  blue 
and  one  of  vermilion,  stirring  thoroughly,  and  taking  care  to 
avoid  too  high  a  color. 

Gray — Raw  umber,  with  a  trilling  amount  of  lamp- 
black. 

Rose  —  Three  parts  of  vermilion  and  one  of  red  lead, 
added  in  very  small  quantities  until  a  delicate  shade  is  pro- 
duced. 

Lavender  —  Mix  a  light  blue,  and  tint  it  slightly  with 
vermilion. 

Sfrarv  —  Chrome  yellow,  with  a  touch  of  Spanish  brown. 

Buff — Two  parts  spruce,  or  Indian  yellow,  raid  one  part 
burnt  sienna. 

HOW   BASSWOOD    MOLDINGS   ARE  MADE. 

Bass  wood  may  be  enormously  compressed,  after  which  it 
may  be  steamed  and  expanded  to  its  original  volume.  Advan- 
tage has  been  taken  of  this  piinciple  in  the  manufacture  of 
certain  kinds  of  moldings.  The  portions  of  the  wood  to  be 
left  in  relief  are  first  compressed  or  pushed  down  by  suitable 
dies  below  the  general  level  of  the  board,  then  the  board  is 
planed  down  to  a  level  surface,  and  afterward  steamed.  The 
compressed  portions  of  the  board  are  expanded  by  the  steam, 
•""o  that  they  stand  out  in  relief. 

BUILDING  BLOCKS  MADE  OF  CORNCOIJS. 

Building  blocks  made  of  corncobs  form  the  object  of  a 
new  Italian  patent.  The  cobs  are  pressed  by  machinery  into 
forms  similar  to  bricks,  and  held  together  by  wire.  They  are 
made  water-tight  by  soaking  with  tar.  These  molds  are  very 
hard  and  strong.  Their  weight  is  less  than  one-third  of  that 
of  hollow  brick,  and  they  can  never  get  damp. 


446 
RED  V.  001)  FINISH. 

The  following  formula  a«*d  directions  Lave  been  highly 
recommended. 

Take  one  quart  spirits  turpv. \tine. 

Add  one  pound  corn  starch. 

Add     %       "     burnt  sienna. 

Add  one  tablespoonful  raw  linseAl  oil. 

Add     "         *'  brown  Jaj.\  n. 

Mix  thoroughly,  apply  with  a  bnu\\  let  it  stand  say  fif- 
teen minutes;  rub  off  all  you  can  with  -fine  shavings  or  a  soft 
rag,  then  let  it  stand  at  least  twenty-fonr  hours,  that  it  may 
sink  into  and  harden  the  fibers  of  the  wood;  afterward  apply 
two  coats  of  white  shellac,  rub  down  w^l  with  fine  flint 
paper,  then  put  on  from  two  to  five  coats  bt*t  polishing  var- 
nish; afier  it  is  well  dried,  rub  with  water  ami  pumice-stone 
ground  very  fine,  stand  a  day  to  dry;  after  being  washed 
clean  with  chamois,  rub  with  water  and  rotten-stone;  dry, 
wash  as  before  clean,  and  rub  with  olive  oil  unti!  dry. 

Some  use  cork  for  sand-papering  and  polishing,  but  a 
smooth  block  of  hard  wood,  like  maple,  is  better.  When 
treated  in  this  way,  redwood  will  be  found  the  peer  of  any 
wood  for  real  beauty  and  life  as  a  house  trim  or  finish. 

A  NEW  WALL  PLASTER. 

A  new  material  for  use  instead  of  common  plaster  is-  ow 
prepared,  which  offers  many  advantages,  as  it  can  be  apj  vd 
more  quickly,  and  dries  in  less  than  twenty-four  hours.  It 
is  impervious  to  dampness,  and  there  is  no  possibility  of  the 
window  and  door  casings  contracting  or  swelling  and  causing 
cracks,  as  very  little  water  is  required  in  the  mixing.  It  is 
known  as"  Adamant  "  wall-plaster,  and  deserves  its  name,  as, 
when  once  dry,  it  is  very  hard  to-  break.  From  a  sanitary 
point  of  view,  it  is  also  valuable,  as  it  is  non-absorbent. 

A  RELIABLE  CEMENT. 

A  reliable  cement,  one  that  will  resist  the  action  of 
water  and  acids,  especially  acetic  acid,  is  :  Finely  powdered 
litharge,  fine,  dry  white  sand  and  plaster  of  Paris — each 
three  quarts  by  measure  —  finely  pulverized  resin  one  part. 
Mix  ar,d  make  into  a  paste  with  boiled  linseed  oil,  to  which 
a  little  dryer  has  been  added,  and  let  it  stand  for  four  or  five 
hours  before  using.  After  fifteen  hows'  standing,  it  loses 
Strength.  The  cement  is  said  to  ha\v  bcvn  successfully  used 
in  Zoological  Gardens,  London. 


447 
PAVEMENTS. 

Bricks,  impregnated  at  a  warm  temperature  with  as- 
phaltiun,  have  been  successfully  used  in  Berlin,  for  street 
pavement.  After  driving  out  the  water  with  heat,  bricks 
will  take  up  from  fifteen  to  thirty  per  centum  of  bitumen, 
and  the  porous,  brittle  material  becomes  durable  and  elastic 
under  pressure,  the  bricks  are  then  put  endwise  on  a  beton 
bed,  and  set  with  hot  tar.  It  is  said  that  the  rough  usage 
which  the  pavement  made  of  these  bricks  will  stand  is  aston- 
ishing. A  fe\v  yenrs  ago,  in  California,  a  pavement  was  laid 
of  bricks,  those  tint  were  soft-burned  being  selected,  which 
were  sat  Ufa  ted  with  boiling  coal  tar.  They  were  placed  end- 
wise on  a  bed  of  concrete,  and  the  interstices  filled  with  the 
hot  tar.  sind  being  scattered  to  the  depth  of  about  one-half 
(^2)  inch  upon  the  pavement,  and  afterward  swept  off.  And 
now  we  learn  from  an  exchange  that  bricks  impregnated 
with  creosote  or  bitumen  have  been  adopted  for  paving  pur- 
poses in  Nashville,  Term.,  and  with  very  satisfactory  results. 
The  wear  is  very  uniform,  as  the  softer  and  more  porous 
bricks  absorb  more  bitumen,  which  has  the  effect  of  harden- 
ing them,  at  tlri  same  time  making  them  absolutely  imper- 
vious, and  thus  protecting  them  from  the  disintegrating  effect 
of  frost.  It  is  stated  that  pavement  of  this  type,  exposed 
for  three  and  a  half  (3^)  years  to  the  wear  of  fairly  heavy 
traffic,  was.  at  the  end  of  that  period,  found  to  be  in  excel- 
lent condition.  The  process  of  bitumenizing,  however, 
rather  more  than  doubles  the  cost  of  the  brick. 

A  POLISH    FOR  WOOD. 

The  wooden  parts  of  tools,  such  as  the  stocks  of  planes 
and  handles  of  chisels,  are  often  made  to  have  a  nice  appear- 
ance by  Freivjh  pol;shing ;  but  th's  adds  nothing  to  their 
durability.  A  much  better  plan  is  to  let  them  soak  in  lin- 
seed oil  for  a  week,  and  rub  with  a  new  cloth  for  a  few  min- 
utes every  day  for  a  week  or  two.  This  produces  a  beauti- 
ful surface,  and  has  a  solidifying  effect  on  the  wood. 

TO  CALCULATE  THE  NUMBER  OF  SHINGLES 
FOR  A  ROOF. 

To  calculate  number  of  shingles  for  a  roof,  ascertain  num- 
ber of  square  feet,  and  multiply  by  four,  if  two  inches  to 
weather,  8  for  4^  inches;  and  7  1-5  if  5  inches  are  exposed. 
The  length  of  a  rafter  of  one  third  pitch  is  equal  to  three- 
fifths  of  width  of  building,  adding  projection. 


VALUABLE  FIGURES. 

The  following  figures  are  wortfi  remembering,  as  they 
will  save  a  good  deal  of  calculation  and  give  approximately 
accurate  results  with  a  minimum  of  labor  : 

A  cord  of  stone,  three  bushels  of  lime  and  a  cubic  yard 
of  sand,  will  lay  one  hundred  cubic  feet  of  wall. 

Five  courses  of  brick  will  lay  a  foot  in  height  on  a 
chimney. 

Nine  bricks  in  a  course  will  make  a  flue  eight  inches  wide 
and  twenty  inches  long,  and  eight  bricks  in  a  course  will 
make  a  flue  eight  inches  wide  and  sixteen  inches  long. 

Eight  bushels  of  good  lime,  sixteen  bushels  of  sand 
and  one  bushel  of  hair,  will  make  enough  mortar  to  plaster 
one  hundred  square  yards. 

One-fifth  more  siding  and  flooring  is  needed  than  the 
number  of  square  feet  of  surface  to  be  covered,  because  of  the 
lap  in  the  siding  and  matching  of  the  floor. 

One  thousand  laths  will  cover  seventy  yards  of  surface, 
and- eleven  pounds  of  lath  nails  will  nail  them  on. 

One  thousand  shingles  laid  four  inches  to  the  weather, 
will  cover  one  hundred  square  feet  of  surface,  and  five  pounds 
of  shingle  nails  will  fasten  them  on. 

FROSTED  GLASS. 

Verre  Givre,  or  hoar  frost  glass,  is  an  article  now  made 
in  Paris,  so  called  from  the  pattern  upon  it,  which  resembles 
the  feathery  forms  traced  by  frost  on  the  inside  of  the  win- 
dows in  cold  weather.  The  process  of  making  the  glass  is 
simple. 

The  surface  is  first  ground,  either  by  the  sand  blast  or 
the  ordinary  method,  and  is  then  covered  with  a  sort  of 
varnish.  On  being  dried,  either  in  the  sun  or  by  artificial 
heat,  the  vainish  contracts  strongly,  taking  with  it  the  parti- 
cles of  glass  to  which  it  adheres  ;  and,  as  the  contraction 
takes  place  along  definite  lines,  the  pattern  produced  by  the 
removal  of  the  particles  of  glass  resembles  very  closely  the 
branching  crystals  of  frostwork. 

A  single  coat  gives  a  small,  delicate  effect,  while  a  thick 
film,  formed  by  putting  on  two,  three  or  more  coats,  con- 
tracts so  strongly  as  to  produce  a  large  and  bold  design.  By 
using  colored  glass,  a  pattern  in  half-tint  may  be  made  on  the 
color  eel  ground,  and,  after  decorating  white  glass,  the  back 
may  be  silvered  or  gilded. 


449 
PERFECT  MITERING. 

BY   OWEN  B.  MAGINNIS. 

The  many  awkward  ways  in  which  so  many  woodworking 
mechanics  endeavor  to  mark  and  cut  in  soft  and  hard  wood 
moldings,  and  the  botching  results  of  their  efforts,  has  in- 
duced the  writer  to  give  the  following  simple  and  successful 
methods  which  are  perfect  in  their  accuracy. 

The  different  conditions  which  exist  through  the  careless- 
ness of  those  who  precede  him,  when  an  operator  commences 
to  set  in  his  molding,  often  cause  him  much  trouble  and  loss 
of  patience,  as  for  instance,  a  molding  being  run  standing  on 
the  little  rebated  lip  or  a  raised  molding  being  out  of  square, 
or  an  obtuse  angle,  instead  of  a  little  tinder^  or  an  acute 
angle.  This  will  of  course  necessitate,  either  the  re-rebating 
of  the  molding  by  hand,  or  taking  the  arris  of  the  corner  of 
the  panel  sinkage  as  shown  at  A.  Fig.  i.  Then  the  molding 


FIG.  i. 

is  often  stuck  too  thin  for  sinkage,  as  will  be  clearly  seen  on 
the  left  hand  side  of  the  panel  at  B,  and  again  the  surface  of 
the  door,  on  account  of  the  inequalities  of  the  thickness  of 
the  pieces,  especially  on  the  back  side,  often  varies  as  much 
as  iJg  of  an  inch.  This  difficulty  is  easily  overcome  by  the 
following  sure  process. 

Take  a  small  strip,  and,  placing  the  end  of  it  down  in  the 
corner,  mark  the  arrises  with  a  sharp  pocket  knife.  Measure 
these  depths;  in  the  case  shown  here  they  will  be,  for  exam- 
ple, respectively,  ^-inch,  ^-inch,  -jJg-inch,  full,  ^-inch  full, 
and  ^-inch,  scant.  Having  done  this,  make  4  strips,  or  saddles, 


450 

equal  in  width  to  the  different  depths  of  thesinkage,  as  j^-inch 
wide,  ^—fg  wide,  and  so  on,  each  being  about  %-inch  thick  and 
long  enough  to  go  into  the  miter  box  between  the  saw  cuts. 


FIG.  2. 

Plac?  it  in  the  box  as  represented  at  Fig.  2,  with  the  lip  of 
the  molding  resting  on  the  saddle  as  it  will  rest  on  the  door- 
frame, at  the  miter  and  saw  the  left-hand  end  (say  on  the  ^ 
scant  saddle):  To  get  the  neat  and  exact  length  without 
gauging  on  the  door.  From  the  point  where  the  saw  crosses 
the  saddle  at  Fig.  3,  square  across  the  bottom  of  the  box 
with  the  Den-knife.  These  lines  are  the  neat  and  exact 
lengths  for  either  end,  so  if  the  thin  edge  —  B,  Figs,  i  and  3, 
of  the  molding,  be  marked  at  the  opposite  arris,  holding  the 
already  mitered  end  close  into  its  corners  —  and  then  this 
mark  be  placed  at  the  asterisk  or  intersection,  and  the 
molding  sawn  on  the  saddle  necessary  for  the  opposite  cor- 
ner (say  l/2  full  saddle),  and  so  on  all  around  the  panel,  it 
will,  if  cut  out  of  one  piece,  perfectly  utersect  in  its  profile, 
*he  lip  will  come  to  a  close  joint  on  the  frame,  and  the  thin 
sdge  close  to  the  panel.  The  dotted  line  in  Fig.  3  shows 
now  the  molding  should  be  neld  down  in  the  box.  The  best 
way  is  tolry  a  pair  of  pattern  pieces  as  shown  at  Fig.  I  (on 
the  nedBRry  saddle),  trying  the  patterns  in  each  corner. 


r 

?•         miMft 

'  1 

2,                   T        •-+                 n 

1 

x                y                    -        1 

Fig.  3- 

By  this  means  it  will  be  easy  to  find  the  exact  saddle  which 
will  bring  a  good  miter.  Be  sure  they  will  come  right 
tbefore  commencing  to  cut  the  molding  all  round.  If  it  be 
too  thick  for  the  sinkage,  of  course  it  must  be  planed  down 
on  the  back  until  it  is  a  shaving  thin,  so  that  it  will  not  strike 
the  fillet,  but  press  closely  on  the  panel. 

Great  care  should  be  exercised  in  cutting  die  miter  box,  as 


451 

perfect  mitering  is  almost  reliant  on  a  good  box,  cut  exactly 
on  the  angle  of  forty-five  degrees.  To  set  the  level,  lay  o«t 
a  square  on  a  drawing-board  about  four  inches  wide.  Join 
the  opposite  angles  like  at  Fig.  4  (be  certain  it  is  exact  to  a 
hair,  or  the  bevel  will  not  reverse  itself).  Place  the  bevel  on*> 
to  the  lines  joining  the  angles  as  it  lies  on  the  board  and 
mark  the  miter  box  by  it.  This  is  the  only  perfect  way  to 
miter  and  cut  in  raised  moldings,  and  will  always,  without 
error,  assure  accuracy  and  good  mitering. 

Fig.  4. 


Mitering  flush  molding  or  molding  which  does  not  rise 
above  the  surface  of  the  frame  is  comparatively  simple,  and 
is  usually  done  with  a  jack,  except  in  the  case  of  large  mold- 
ing. All  that  is  necessary  is  to  first  miter  the  left-hand  end 
and  mark  the  right  hand. 

The  handiest  way  is  to  commence  at  the  right-hand 
corner  next  to  you,  and  work  to  the  farthest  corner,  and  soon 
all  round,  returning  to  the  one  started  from.  Should  the 
lengths,  when  placed  in  the  panel  before  drawing  down,  be 
too  long,  take  a  rebate  plane,  shaving  off  until  they  be  a  snug^ 
tight  fit. 

THE  VENTILATION  OF  BUILDINGS. 

Perhaps  no  single  feature  of  modern  architectural  construc- 
tion is  likely  to  secure  such  immediate  regard  in  the  near 
future,  and  is  already  so  conspicuously  engaging  the  attention 
of  the  foremost  men  in  the  profession,  as  that  of  proper  ven- 
tilation. Nor  can  it  be  denied  that  no  feature  is  more  im- 
portant for  health  considerations  in  private  homes,  office 


452 

buildings  and  public  institutions,  than  the  securing  of  a 
steady  supply  of  pure  air  and  the  coincident  and  correspond- 
ing removal  of  the  vitiatec1  air,  so  that  the  atmosphere  in  the 
rooms  is,  at  all  times,  fresh  and  pure.  The  two  points  cov- 
ered in  the  last  sentence  constitute  what  is  known  as,  and  is 
technically  termed. ."ventilation." 

The  expedients  for  obtaining  a  supply  of  fresh  air  to  the 
room,  so  that  there  is  a  constant  dilution  and  consequent 
bettering  of  the  atmosphere,  are  comparatively  simple. 
They  merely  imply  that  the  air  warmed  by  the  hot-air  fur- 
nace or  steam  coils  in  the  cellar  be  taken  from  a  place  where 
It  is  pure  (not,  for  instance,  above  a  cesspool),  that  the  ducts 
in  cellar,  through  which  the  air  travels,  be  air-tight  (prefer- 
_ly  ;i  .Abstracted  of  No.  22  or  No.  24  galvanized  iron, 
rather  than  of  wood),  and  that  some  automatic  means  be 
adopted  to  regulate  the  temperature  of  the  air  supplied  to 
the  rooms,  without  shutting  off  such  air  supply.  Or,  when 
steam  radiators  are  in  rooms,  that  they  be  placed  below  win- 
dows, and  air  pass  by  means  of  proper  orifices  from  outside 
through  the  radiators. 

Furthermore,  in  large  structures,  a  fan  driven  by  electric 
or  steam  power  is  often  instituted  for  forcing  in  a  larger 
amount  of  fresh  air  than  could  be  secured  by  the  natural 
suction  of  the  warmed  air. 

But  the  mere  supply  of  warmed  fresh  air  to  the  rooms  is 
not  enough.  For  note,  if  the  air  in  the  room  has  no  escape, 
it  does  not  take  long,  whatever  the  fresh  air  supply,  before 
tbe  vitiated  air  contaminates  and  makes  foul  the  air  as  it 
enters  the  apartment.  To  open  the  windows  is  the  remedy 
which  the  uninitiated  at  once  suggest,  and,  in  fact,  in  most 
houses  this  is  the  only  palliative  at  hand. 

It  is,  however,  one  of  the  first  principles  of  ventilation, 
that  the  windows  must  not  enter  as  an  expedient.  In  a 
properly  ventilated  building  the  windows  should  never  be 
open  when  people  are  in  the  rooms,  at  least  in  the  winter 
months.  For,  opening  the  windows  secures  the  admission  of 
cold  air  in  bulk,  but  does  not  remove  the  foul  air,  and  more 
especially  causes  pneumonia-giving  draughts,  and  chills  the 
room,  and  in  this  way  more  damage  is  done  than  by  even  the 
presence  itself  of  vitiated  air  in  the  rooms. 

A  warm  or  hot  room  does  not  necessarily  signify  an  im- 
pure atmosphere;  while  we  may  have  a  room  cold  and  the 
atmosphere  still  terribly  ynpure.  The  unthinking  never 
take  this  into  account,  and  are  apt  to  confuse  the  term  warm 
with  impure,  and  the  term  cold  with  pure  atmosphere,  as  far 
as  the  rooms  they  are  in  are  concerned. 


453 

The  proper  way  to  remove  the  vitiated  air  is  by  means  et 
vent-ducts,  or  vertical  flues  leading  from  the  rooms  to  the 
roof  of  the  building.  These  flwes  should  have  an  aggregate 
cross-sectional  area  at  least  equal  to,  and  preferably  about 
ten  per  cent,  greater  than,  the  cross-sectional  area  of  the 
fresh  air  inlets;  and  should  be  situated  on  the  opposite 
(preferably  diagonally  opposite)  side  of  the  room. 

These  vent -ducts  should  have  openings  controlled  by 
registers,  near  the  floor  and  near  the  ceilings  of  the  rooms, 
but  the  two  registers  should  not  be  opened  at  the  same  time. 
The  cross-sectional  area  of  the  registers  should  be  twenty-five 
per  cent,  more  than  that  of  the  vent-ducts. 

The  bottom  register  is  the  one  ordinarily  to  be  used;  for 
the  heavy,  vitiated  air  sinks  to  the  floor,  while  the  fresher,  un- 
polluted air  rises.  When  the  people  in  the  room  are  smoking 
profusely,  it  is  better  to  close  the  bottom  and  open  the  top 
registers  of  the  vent-ducts,  for  the  smoke  rises  to  the  top, 
and  is  then  more  speedily  removed. 

These  vent-ducts  cause  a  gentle  draught  in  the  same  way 
that  a  chimney  of  a  steam  boiler  or  hot-air  furnace  does. 
The  temperature  in  the  room  being  higher  than  that  of  the 
external  air,  the  temperature  in  the  vent-ducts  is  also  higher, 
and  consequently  a  draught  or  removal  of  the  vitiated  air  is 
secured,  the  amount  depending  on  the  area  and  height  of  the 
duct,  and  the  difference  of  temperature  between  the  ex- 
ternal air  and  the  air  in  the  room.  This  system  is  known  as 
that  of  natural  ventilation. 

To  make  this  removal  of  vitiated  air  still  more  rapid  than 
is  secured  by  the  natural  draught  just  mentioned  and  ex- 
plained, one  of  several  expedients  may  be  adopted.  An 
exhaust-fan,  driven  by  steam  or  electric  power,  may  be  placed 
near  the  top  of  vent-duct,  and  the  air  exhausted  from  duct  by 
means  of  this  fan,  thus  increasing  the  fresh  air  supply  through 
fresh  air  inlet.  This  is  frequently  adopted  in  public  build- 
ings, where  the  rooms  are,  at  times,  full  of  people.  Or  the 
temperature  of  the  air  in  the  vent-ducts,  and  consequently 
the  drabght  and  the  removal  of  vitiated  air,  may  be  in- 
creased by  any  of  the  following  means: 

1.  Gas  jets  may  be  burned  in  the  vent-flues  near  the  bot- 
tom. 

2.  Steam  risers,   through  which  steam  of  high  or  low 
pressure  circulates,  may  run  through  the  vent -ducts. 

3.  Such  steam  risers  may  have  a  large  coil  near  top   or 
right  above  vent-flues  proper. 

For  private  homes  and  dwellings;  natural  ventilation 
suffices.  For  public  buildings  and  large  halls,  either  the  fan 


454 

or  the  stt?am  system  should  be  preferably  adopted.  The  gag 
jets  give  out  a  comparatively  little  additional  heat,  but  are 
mexpensive  in  first  cost,  and  in  running  expense. 

In  a  paper  "  On  the  Relative  Economy  of  Ventilation  by 
Heated  Chimneys  and  Ventilation  by  Fans,"  read  by  Prof. 
Wm.  P.  Trowbridge,  of  the  School  of  Mines,  Columbia  Col- 
lege, before  the  American  Society  of  Mechanical  Engineers, 
Prof.  Trowbridge  decides  that  in  all  cases  of  moderate  ven- 
tilation of  rooms  or  buildings,  where,  as  a  condition  of  health 
or  comfort,  the  air  must  be  heated  before  it  enters  the  rooms, 
and  spontaneous  ventilation  is  produced  by  the  passage  of 
this  heated  air  upward  through  vertical  flues,  such  ventila- 
tion, if  sufficient,  is  faultless  as  far  as  cost  is  concerned.  He 
consideres  this  a  condition  of  things  which  may  be  realized 
in  most  dwelling  houses,  and  in  many  halls,  school-rooms  and 
public  buildings,  inlet  and  outlet  flues  of  ample  cross-section 
being  provided,  and  the  heated  air  being  properly  distrib- 
uted. 

If,  however,  starting  from  this  condition  of  things,  a  more 
active  ventilation  is  demanded,  the  question  of  relative  econ- 
omy of  fan  and  heated  chimney  is  not  so  simple  a  problem. 
Prof.  Trowbridge  points  out  that  ventilation  by  chimneys  is 
disadvantageous  under  one  point  of  view  in  any  case,  viz  :  the 
difficulty  of  accelerating  the  ventilation  at  will  when  larger 
quantities  of  air  are  needed  in  emergencies;  while  the  fan 
or  blower  possesses  the  advantage  in  this  respect,  that  by  in- 
creasing the  number  of  revolutions  of  the  fan  the  head  or 
pressure  is  increased.  This  latter  fact  makes  the  fan  prefer- 
able for  the  ventilation  of  hospitals  or  public  buildings  of 
considerable  magnitude,  whenever,  as  is  customary,  the  activ- 
ity of  the  ventilation  must  be  varied  occasionally. 

Where  the  power  required  is  only  a  small  fraction  of  a 
horse-power,  as  in  ventilating  single  large  rooms  or  small 
buildings,  Prof.  Trowbridge  concludes  it  to  be  evident  that  as 
regards  cost  of  fuel  and  the  care  and  attention  required,  ven- 
tilation by  heated  chimneys  is  preferable,  except,  of  course, 
for  cases  where  a  fan  is  driven  by  machinery  employed  for 
•ther  purposes  than  ventilation,  the  cost  of  attendance  charge- 
able to  ventilation  being  then  trifling  and  the  fan  evidently 
being  more  appropriate. 

The  construction  of  the  building,  of  course,  enters  as  an 
important  factor,  and  often  precludes  the  adoption  of  the  ex- 
haust-fan system.  In  large  structures  it  is  always  important 
to  take  into  account,  and  decide  upon,  the  system  of  ventila- 
tion before  the  plans  of  the  building  proper  are  finished  or 
finally  adopted. 


45i> 
BURYING  A  SCREW  HEAD  OUT  OF  SIGHT. 

To  get  the  heads  of  nails  and  screws  out  of  sight,  where 
glue  can  be  used  without  any  objection,  just  raise  up  a  chip 
with  a  thin  paring  chisel,  as  shown  in  the  drawing,  and  then 
set  the  nail  in  solid.  This."  leaf"  can  be  covered  with  a  coat- 
ing of  glue  and  laid  back  again  in  place,  where  it  must  fit  on 
all  sides  to  perfection.  A  dead  weight  will  hold  everything 
in  place  till  the  glue  dries,  and  a  few  moments  with  the 
scraper  makes  the  job  complete.  It  will  add  to  the  nicety  of 
the  work  to  draw  lengthwise  with  the  grain  two  deep  cuts 
with  a  thin  case-knife  just  the  width  of  the  chisel,  and  this 
keeps  the  sides  of  the  chips  from  splitting.  The  chisel  should 
be  set  at  a  steep  angle  at  first  till  the  proper  depth  is  reached, 
and  then  made  to  turn  out  a  cut  of 
even  thickness  until  there  is  room  to 
drive  a  nail.  If  too  sharp  a  curve  is 
given,  the  leaf  is  likely  to  break  apart 
in  being  straightened  out  again.  In 
blind  nailing  a  narrow  chip  is  taken 
'  with  a  tool  made  especially  for  this 
purpose,  that  lifts  the  cut  just  high 
enough  to  let  in  the  nail  on  the  slant, 
a  set  slightly  concaved,  being  used  to 
keep  it  from  ever  slipping  off  the 
head,  and  the  upraised  cut  driven 
down  again  with  the  hammer. 

HIP  AND  VALLEY  ROOF  FRAMING. 

A  simple  way  of  laying  out  a  hip  or  valley  roof  and 
finding  the  length  of  jack  rafters,  cuts  and  bevels,  is  shown 
in  the  accompanying  sketch.  The  method  followed  is  com- 
paratively simple  and  easily  understood. 

Lay  down  the  plan  of  the  building  A^  B,  C,  D,  find  the 
center  line  of  the  ridge  E  F,  and  show  the  plan  of  hips  A  F 
and  B  F,  also  the  jacks  G H and  IK. 

To  find  the  length  of  the  common  or  straight  side  rafters, 
lay  off  on  the  ridge  line  E  F  the  height  of  the  pitch  E  M. 
From  the  point  A7",  which  is  the  outside  edge  of  the  wall 
plate,  join  N  M.  This  will  give  N  M  as  the  extreme 
length,  on  the  upper  edge,  of  the  common  rafter  which  is  to 
stand  over  the  seat  E  N. 

,  In  order  to  find  the  length  of  the  hip  rafurs  whichi  will 
stand  over  the  seats  C  E  or  B  F,  draw  the  line  O  E 
square  with  the  line  E  C,  and  make  O  £=M  E  the  height 
of  the  pitch.  Join  the  point  C  with  the  point  Ot  thus 


456 

obtained,  which  will  give  the  length  to  the  hip  rafter  on  its 
upper  edge. 

The  length  of  the  jack  rafters  is  generally  obtained  by 
direct  measurement,  but  the  following  method  will  be  found 
correct.  Produce  the  line  N E>  and  make  N  P  equal  to 
the  length  of  the  common  rafter,  so  that  N  P=M N^  join 
P  C,  which,  will  equal  C  O;  produce  the  seat  of  the  jack 

JD 


rafters  k  i  and  g  h,  until  they  intersect  P  C  in  /  and  m9 
and  then  /  /  and  g  m  will  be  the  correct  lengths  for  the 
jack  rafters. 

In  raising  a  roof  of  this  description,  it  is  usual  to  cut  the 
ridge  E  F  and  the  common  rafters  which  abut  against  it  at 
each  end  as  at  R  F.  In  placing  them  in  position  they  are 
fastened  plumb  over  their  seats  by  braces,  and  the  side 
rafters  are  placed  each  against  its  mate,  as  /  against  /,  2 
against  2,  j»  against  j»,  and  so  on. 

When  all  the  side  rafters  are  in  position,  the  hips  are 
inserted,  and  their  accompanying  jacks. 

PAINTING  AND  VARNISHING  FLOORS. 

A  French  writer  observes  that  painting  floors  with  any 
color  containing  white  lead  is  injurious,  as  it  renders  the 
Vrood  soft  and  less  capable  of  wear.  Other  paints  without 
white  lead,  such  as  ochre,  raw  umber  or  sienna,  are  not  in- 
jurious and  can  be  used  with  advantage.  Varnish  made  of 
drying  lead  salts  is  also  said  to  be  destructive,  and  it  is 
reccpmmended  that  the  borate  of  manganese  should  be  used 
to  dispose  the  varnish  to  dry.  A  recipe  for  a  good  floor  var- 


457 

nish  is  given  as  follows:  Take  two  pounds  of  pure  whit* 
borate  of  manganese,  finely  powdered,  and  add  it  little  by 
little  to  a  saucepan  containing  ten  pounds  of  linseed  oil,  which 
is  to  be  well  stirred  and  raised  to  a  temperature  of  360°  Fahr, 
Heat  100  pounds  of  linseed  oil  in  a  boiler  till  ebullition  tak«e 
place;  then  add  to  it  the  first  liquid,  increase  the  heat  and 
allow  it  to  boil  for  twenty  minutes.  Then  remove  from  tbft 
fire  and  filter  the  solution  through  cotton  cloth.  The  var- 
nish is  then  ready  for  use,  two  coats^  of  which  may  be  used, 
with  a  final  coat  of  shellac,  if  a  brilliant  polish  is  required. 

A  COLOSSAL  STICK  OF  TIMBER. 

A  colosal  stick  of  lumber  from  Puget  Sound  has  been  con* 
tributed  to  the  Mechanics  Exhibition  at  San  Francisco.  Its 
length  is  151  feet,  and  it  is  twenty  by  twenty  inches  through. 
It  is  believed  to  be  the  longest  piece  of  timber  ever  turned  out 
of  any  saw  mill. 

A  few  years  ago  mechanics  cared  very  little  about  winter 
work  of  any  kind.  They  rather  looked  forward  with  pleas* 
ure  to  the  prospects  of  a  long  rest.  Things  have  been  chang- 
ing recently,  and  the  tendency  now  is  to  secure  all  the  winter 
work  possible:  One  reason  is,  there  are  more  building  and 
Joan  associations,  more  insurance  societies,  more  lodges  and 
more  organizations  of  one  kind  and  another,  all  of  which 
must  be  kept  up.  Besides,  there  is  an  increasing  amount  of 
work  that  has  heretofore  been  done  in  summer.  The  cost  of 
labor  in  a  good  many  vocations  is  less  in  winter  than  it  is  in 
summer,  owing  to  the  small  amount  to  be  done  and  the  greater 
number  seeking  it. 

PLASTER  FOR  MOLDINGS. 

Where  walls  and  ceilings  are  to  be  molded  whilst  yet  in  a 
plastic  state,  some  decorators  are  using  a  fibrous  plaster,  with 
(he  object  of  securing  greater  firmness  and  tenacity.  The 
idea  itself  is  not  new,  animal  hair  having  formerly  been  inter- 
mixed with  lime,  but  this  is  a  new  application.  In  England 
and  France  a  fine  wire  netting  is  at  times  inserted  between 
two  courses  of  plaster,  to  afford  greater  firmness  in  holding 
picture  frames.  The  tenacity  of  some  of  the  old  moldings 
in  old  New  York  houses,  whilom  aristocratic,  is  very 
remarkable,  retaining  as  they  do  their  original  sharpness  of 
outline. 


458 
THE  SWEATING  OF  CHIMNEYS. 

The  sweating  of  chimneys  is  now  believed  to  be  due  to 
condensation  of  the  moisture  in  the  air  that  is  confined  in  a 
poorly  ventilated  chimney  flue.  The  trouble,  as  our  corre- 
spondent indicates,  is  chiefly  to  be  found  occurring  in  small 
chimneys,  and  in  such  chimneys  whose  flues  start  from  the 
second  or  third  story  of  a  building.  The  sweating  is  the 
most  copious  when  a  fire  is  started  in  a  place  that  has  been 
for  some  time  in  disuse,  or,  in  other  words,  when  the  flue  is 
cold.  The  humidity  of  the  air  is  a  large  factor  in  the 
phenomena  of  sweating.  If  the  air  be  charged  with  moisture, 
the  flue  cold,  and  a  fire  newly  kindled,  the  conditions  are 
favorable  for  sweating.  It  is  only  under  these  favorable 
conditions  that  a  well- ventilated  chimney  will  begin  to  sweat, 
but  the  sweating  will  not  continue.  If  sweating  should 
continue  in  a  chimney  after  a  fire  is  fairly  under  way,  it  can 
be  safely  concluded  that  the  chimney  needs  an  opening  near 
the  ground  to  provide  a  better  circulation  of  air  within  the 
flue.  It  may  be,  as  our  correspondent  suggests,  that  rain 
may  beat  in  and  cause  the  same  effect  as  sweating,  especially 
where  the  rain  has  continued  for  several  days  together,  and 
in  that  case  a  cowl,  such  as  has  been  lately  described  in 
"Building,  in  House  and  Stable  Fittings,"  would  cure  the 
disease  by  excluding  the  rain;  but  such  occurrences  are 
exceedingly  rare,  and  we  have  seen  chimneys  guilty  of  sweat- 
ing that  were  provided  with  the  most  approved  form  of  cowl, 
:.^1  the  remedy  applied  has  been  to  insert  an  air-brick  at  the 
nase  of  the  chimney  to  secure  better  ventilation,  so  as  to 
lessen  condensation,  and  the  device  has  proved  successful. 
Cowls  prove  useful  only  so  far  as  they  promote  ventilation 
by  increasing  the  circulation  within  the  chimney  flue.  A 
cowl  may  be  so  improperly  applied  to  a  flue  as  to  promote, 
instead  of  abolishing:,  sweating.  The  main  point  is  to  pro- 
vide an  ingress  of  air  sufficient  to  tax  the  extractive  capacity 
of  the  cowl  that  is  used. 

ELECTKIC  LIGHTS  IN  GEEMANY. 

According  to  Dr.  Schilling,  the  number  of  electric  light  . 
installations  in  the  13  principal  towns  of  Germany  has  in- 
creased during  the  last  two  years  from  131  to  604;  the  num- 
ber of  arc  lamps  has  increased  from  591  to  3,280,  and  the 
number  of  incandescents  from  10,403  to  50,469.  The  num- 
ber of  gas  lamps  in  these  13  towns  is  1,221,882,  and  there- 
fore, lamp  for  lamp,  electricity  furnishes  about  four  per  cent 
of  the  total  illumination  • 


459 

SMOKY  CHIMNEYS  AND  HOW  TO  CURE  THEM. 
A  smoky  chimney  is  a  complaint  we  are  often  called  upom 
to  deal  with,  and  the  best  way  of  building  chimneys  whick 
should  not  smoke  into  the  rooms,  and  of  remedying  existing 
chimneys  which  are  liable  to  do  so,  is  a  matter  of  great  im- 
portance to  estate  clerks  of  works.  There  are  many  small 
matters  in  building  new  chimneys  which,  together,  may  be  a 
means  of  preventing  them  from  smoking  at  the  wrong  end ; 
but  my  intention  at  present  is  to  deal  crJy  with  the  shaft  or 
stack,  or  portion  outside  the  roof,  and  my  object  is  not  to 
give  ornamental  elevations  of  chimney  heads,  which  are  un- 
necessary for  the  purpose  of  this  article,  but  to  explain  a  way 
of  forming  them  which  I  have  many  timesfound  to  give  relief 
to  inveterate  smokers.  A  common  shaft,  such  a  one  as 
would  be  adapted  for  existing  old  cottages,  is  2^  bricks  «r 
I  ft.  10%  in.  in  width,  and  in  my  opinion  none  should  be  lesi 
than  this,  with  a  9-inch  earthenware  flue-pipe  built  in  solid; 
this  I  usually  commence  on  the  damp  course,  which  should 
be  just  above  the  flashings  of  roof.  As  the  area  of  the  round 
pipe  is  smaller  than  the  14-inch  by  g-'mch  brick  flue 
on  which  it  is  placed,  a  quicker  current  of  air  or  draught  is 
thereby  generated,  and  in  windy  weather  a  check  is  given  to 
sudden  down-draughts.  Another  advantage  in  a  flue-lined 
stack  is  that  there  is  no  danger  of  the  brickwork  cracking 
when  the  soot  in  the  flue  is  on  fire,  and  which,  owing  to  the 
scarcity  of  chimney-sweeps,  is  often  the  case  in  countryplaces. 
Stoneware  drain  pipes,  however,  are  quite  unfit,  as  they  are 
Kable  to  split  with  the  heat  ;  but  the  tubes  made  of  fire-clay 
or  terra-cotta,  only  should  be  used.  Another  help  is  to  keep 
the  stack  dry  ;  a  damp  flue  is  generally  a  smoky  one,  and  if  a 
fire  is  lighted  in  the  fire-place,  say,  of  a  disused  bed-room,  it 
is  a  common  occurrence  to  see  the  smoke  puff  down  violently 
and  the  chimney  is  said  to  have  a  down-draught,  and  by  many 
people  is  assumed  to  be  badly  constructed,  whereas,  perhaps, 
it  may  be  built  in  the  best  possible  manner  except  that  it  will 
not  keep  out  rain  and  damp.  '  The  rain  may  come  through  the 
sides  of  the  stack,  or  it  may  comedownward  through  the  head %, 
at  any  rate  the  chimney  for  some  distance  from  the  top  is,  in 
wet  weather,  cold  and  soppy.  I  roof  the  chimney  top  with 
plain  tiles,  with  the  object  of  protecting  the  head  and 
permitting  the  rain  to  drop  off  at  the  eaves  instead 
of  running  down  the  stack  and  making  the  flue  cold, 
and  'the  stack  outwardly  black  and  soot  stained  I 
bed  the  tiles  in  cement,  using  copper  nails  driven  into  the 
latter  through  the  pin  holes — or  a  plain,  cemented  we 


460 

ing  looks  fairly  well.  But  by  forming  the  covering  with  tiles 
a  good  drip  is  obtained,  which  is  not  so  readily  done  with 
cement.  Another  point  is  not  to  make  the  slope  or 
pitch  of  a  suitable  angle,  and  this,  in  my  opinion, 
should  be  about  45  degrees,  as  I  find  that  inclination  most 
effectual;  when  the  wind  strikes  the  slope  it  takes  an  upward 
direction,  and,  as  a  matter  of  course,  carries  the  smoke  with 
it. 

Some  time  since  a  gentleman  living  by  the  seaside  was 
much  troubled  with  smoky  chimneys,  and  asked  me  what 
was  the  best  thing  to  do  ;  I  told  him  near  about  what  I  have 
just  now  written,  and  a  short  time  afterward  I  received  a  letter 
(which  I  must  confess  somewhat  scared  me)  saying  he  had 
decided  to  pull  down  his  chimneys  and  rebuild  them  on  my 


principle,  and  desired  me  to  order  for  him  two  truck  loads  of 
George  Jennings'  flue  pipes  at  once.  This  I  did,  and  waited 
anxiously  for  the  result;  at  last  I  was  gratified  by  hearing 
"  Chimneys  are  a  great  success,"  but  it  was  summer  time, 'and 
I  was  not  so  sure  how  they  would  act  in  cold,  boisterous 
weather  by  the  seaside,  where  every  patented  smoke-curer 
had  apparently  been  tried  by  some  one  or  other  ;  but  eventu- 
ally I  was  glad  to  learn  that  they  continued  to  draw  well. 
*fy  I  have  proved  this  system  of  chimney  stack  building  to  be 
good  in  a  large  number  of  cases ;  for  instance,  my  office 
chimney  is  directly  under  the  branches  of  a  large  tree,  and 
the  fire  is  on  the  hearth,  yet  I  am  never  troubled  with  smoke. 
For  economizing  heat  in  single  houses  or  detached  cot- 
tages, we  all  know  it  is  the  best  plan  to  get  the  chimney  on 
the  inside,  and  not  forming  a  portion  of  the  outer  walls,  as  in 
the  latter  case  they  are  much  more  likely  to  smoke,  and  we 
also  know  that  register  grates,  or  grates  with  doors  a  few 
inches  above  the  fire,  generally  make  the  fire  draw  ;  they  not 
only  draw  the  smoke,  but  a  greater  portion  of  the  heat  as 
well,  and  necessitate  getting  very  close  to  the  fire  to  obtain  a 
portion  of  the  heat  going  up  the  chimney.  To  my  mind, 
there  is  nothing  to  equal  a  fire  on  the  hearth,  and  wood,  if 
Vou  can  get  it,  in  preference  to  coals. 

There  is  much  might  be  said  about  set-offs  in  flues,  and  I 
know  they  are  objected  to  as  a  rule,  but  I  believe  a  chimney 
with- one  or  two  set-offs  is  all  the  better  for  it.  I  also 
believe  chimney  heads  built  in  cement  mortar  true  economy; 
the  latter  makes  good  work  and  looks  well,  long  after  chim- 
ney heads  built  with  lime  mortar,  which  soon  show  startling 
mortar  joints  and  crumbly  bricks.  How  often  do  we  find 
old  chimney  heads  want  repointing,  for  the  wcather  loosens 
the  mortar  and  the  birds  carry  it  away. 


461 

The  summary  of  my  experience  is  briefly  this: 

1.  Put  a  damn  course  to  new  chimneys,  or  insert  one  in 
old  chimneys. 

2.  Line  the  chimneys  with  fine  pipes  above  the  damp 
course. 

3.  Roof  the  chimney  tops 'carefully. 

4.  Don't  forget  a  good  projecting  eaves-drip  to  the  chim- 
ney-head. 

4.    Build  the  heads  with  cement  mortar. 

FACTS  ABOUT  FURNACES. 

In  February,  1881,  the  committee  of  hygiene  of  the  Medi- 
cal Society  of  Kings  County  rendered  a  report,  which  is 
published  in  full  in  the  proceedings  of  that  society,  upon 
catarrh,  and  whether  ^that  disease  was  aggravated  by  resi- 
dence in  cities.  The  opinions  of  a  large  number  of  phy- 
sicians of  long  experience  were  obtained,  and  their  testimony 
showed  "that,  though  climatic  and  city  influences  have  much 
to  do  with  the  creation  of  catarrh,  yet  defective  heating, 
lighting,  airing,  sunning  and  drainage  of  houses,  with  im- 
proper views  as  to  air,  clothing,  bathing  and  exercise,  are 
the  main  causes,"  Individual  physicians  laid  special  stress 
upon  individual  influences,  as  "dry  and  irritating  air  from 
villainous  furnaces,  increased  furnace  heat  and  artificial 
methods  of  living." 

Furnace  air  per  se  is  not  so  unwholesome,  but  it  is  the 
absence  of  ventilation  which  makes  it  so.  If  a  furnace  is  of 
sufficient  size  to  warm  a  building  without  opening  every 
draft  and  heating  the  fire-pot  red-hot,  and  if  the  fresh  air 
supply  is  taken  from  a  proper  source  and  not  from  a  damp 
area  or  unclean  cellar;  and,  furthermore,  if  there  are  suffi- 
cient openings  at  the  top  of  the  house  to  allow  the  impure 
air  which  rises  to  that  point  to  escape  and  thus  cause  a  con- 
stant circulation  of  sufficiently  warmed  but  not  overheated 
air  through  the  house,  under  these  conditions  a  furnace  is 
not  objectionable. 

Furnaces  are  often  badly  located.  It  is  easier  to  force 
warm  air  through  a  furnace  flue  fifty  feet  away  from  the 
prevalent  wind  than  ten  feet  in  the  opposite  direction. 
Mence  the  furnace  should  be  placed  nearest  the  northern 
side  of  the  building,  or  two  should  be  provided.  Hot-air 
flues  should  not  be  carried  for  any  distance  through  cold  cel- 
lars, halls  or  basements,  as  they  will  become  chilled,  and 
will  not  draw  without  being  cased  With  some  non-conducting 
material,  as  mineral  wool. 


462 

Don't  set  a  furnace  in^a  pit,  especially  in  a  wet  soil  where 
water  will  collect  after  every  rain  storm,  but  stand  it  on 
brick  arches,  so  as  to  raise  it  above  the  ground  ;  also  cement 
the  pit.  It  is  unfortunately  very  common  to  find  such 
depressions  filled  with  water ;  this  causes  rusting  of  the  fur- 
nace itself  and  damp  in  the  cellar.  In  very  many  houses 
occupied  by  persons  of  means,  the  furnaces  are  no  longer 
used,  but  have  been  replaced  by  open  fires.  This  is  costly 
comfort,  but  it  is  a  commendable  plan,  as  k  furnishes  ample 
ventilation  to  the  living  rooms.  It  is  desirable  that  one  room 
should  at  least  be  thus  supplied  with  a  careful  and  sanitary  fire. 

Where  fresh-air  inlets  are  carried  from  the  house  drain  to 
the  front  of  a  house  at  the  yard  level,  they  should  not  be 
located  near  to  the  cold-air  supply,  as  there  is  a  chance  that 
during  heavy  states  of  the  atmosphere  a  down-draft  may  be 
created,  and  the  foul  air  sucked  into  the  air  box  and  thence 
upward  into  the  house.  Registers  should  never  be  placed  at 
die  floor  level,  as  they  will  collect  dust  and  sweepings,  which 
are  liable  to  take  fire. 

Furnaces  with  heavy  eastings  heat  slowly  and  are  less  easily 
cracked  or  warped,  and  they  cool  more  slowly,  so  that  the 
heat  evolved  is  more  uniform.  It  is  well  to  retain  the  air 
close  to  the  fire-pot,  and  thus  keep  it  longer  in  contact  with 
the  fire-heating  surface. 

Water  pans  are  often  badly  arranged  so  that  they  admit 
dust,  and  as  they  are  seldom  cleaned  that  may  become  offen- 
sive. They  should  always  be  supplied  by  a  ball-cock  so  as  to 
be  automatic,  rather  than  by  a  stop-cock  which  has  to  be 
opened  by  a  servant,  who  may  be  neglectful. 

Attempts  have  been  made  to  filter  the  air  before  entering 
the  furnace,  but  they  usually  fail.  A  screen  of  galvanized  iron 
wire  of  1-16  mesh  will  exclude  most  floating  material  from 
the  air.  The  air  supply  is  sometimes  taken  from  the  attic, 
but  it  is  apt  to  be  dusty  and  impure.  Others  take  it  from 
vestibules  of  halls  or  piazzas,  which  are  not  bad  places. 

STEAM  vs.  HOT-WATER  HEATING. 

Hot  water  as  a  heating  agent  is  one  of  the  oldest  in  use, 
*nd  has  a  number  of  advantages  in  its  favor.  For  mild 
climates  it  answers  very  well.  For  northern  latitudes,  how- 
ever, and  in  countries  such  as  Canada  and  most  of  our  north- 
ern States,  having  long,  severe  winters,  hot-water  heating  is 
not  in  general  use  on  account  of  the  following  objections: 


High  First  Cost — Hot  water,  as  generally  used,  only- 
gives  off  two-thirds  the  amount  if  IK  at  per  square  foot  of 
radiating  surface  which  steam  will  give  under  similar  cir- 
cumstances. To  get  the  same  results  as  from  steam  it 
therefore  requires  about  fifu  per  cent  more  of  radiators, 
and  a  corresponding  increase  of  piping 

Added  to  the  expense  of  this  extra  material  is  that  of 
labor,  which  increases  in  the  same  proportion,  thus 
making  the  entire  first  cost  of  hot  water  about  one- 
third  higher  than  steam 

Leakage — As  all  the  pipes  are  continually  full  of  water, 
any  leakage  will  rapidly  flood  the  house,  causing  trouble 
and  damage.  With  steam ,  the  flow-pipes  contain  no  water 
whatever,  and  the  return  drip-pipes  but  very  little,  so 
that  in  event  of  a  leakage  the  w-ate  would  be  discovered 
and  stopped  long  before  it  could  do  any  damage. 

No  Way  to  Shut  Off—  We  have  never  yet  seen  a  hot 
water  radiator  which  can  be  turned  off  and  yet  allow  the 
water  within  it  to  flow  back  to  the  boiler,  the  construc- 
tion of  the  radiator  being  such  that  all  the  water  must 
circulate  up  and  down  between  divisions  connected 
alternately  at  the  top  arid  bottom.  » 

When  the  radiator  is  turned  off,  these  divisions  still  re- 
main full  of  water  which  has  no  chance  to  run  off.  It  is 
therefore  necessary  to  keep  all  the  radiators  in  the  house 
running  all  the  time,  or  else  take  the  chan?es  of  their 
freezing  and  giving  trouble  if  they  are  shut  off.  Now 
there  are  certain  rooms  in  almost  every  house,  such  as 
guest-rooms,  which  are  only  occupied  occasionally,  and 
it  would  be  a  useless  expense  and  inconvenience  to  keep 
them  constantly  warmed.  The  advantage  of  steam  over 
hot  water  in  this  respect  is  evident.  With  steam  you  can 
shut  off  any  radiator  you  please,  and  keep  every  room  in 
your  house  at  the  exact  temperature  disired,  without  in- 
convenience or  waste  of  heat. 

Freezing  and  Bursting — It  is  a  curious  fact  that  hot 
water  will  cool  down  and  freeze  much  quicker  than  ordin- 
ary water  under  the  same  circumstances.  The  first  effect 
in  boiling  water  is  to  drive  off  all  its  air, hence, becoming 
more  solid  and  condensed,  it  is  very  susceptible  to  cold 
and  will  freeze  very  easily.  If  the  fire  in  the  boiler  from 
any  reason  goes  out,  the  water  of  course  soon  stops  circu- 
lating, and  in  cold  weather  the  pipes  will  rapidly  freeze 
and  burst.  Many  instances  are  on  record  where  immense 
damage  has  been  done  from  this  cause.  The  use  of  steam, 
on  the  other  hand,  entirely  precludes  this  cause. 


464 

Difficulty  of  Regulation,.— In  zero  weather  it  is  difficult  to 
keep  warm  by  hot  water,  unless  there  is  a  great  amount  of 
heating  surface,  and  then  in  mild  weather  you  aiv  liable  at 
any  time  to  have  too  much  heat.  This  is  especially  notice- 
able in  any  sudden  change  of  temperature. 

Hot  water,  being  slow  in  acquiring  heat  and  slow  in  part- 
ing with  it,  is  consequently  difficult  to  regulate  with  any 
degree  of  satisfaction. 

This  feature  is  seen  in  greenhouse  heating  particularly. 
When  the  sun  is  shining,  on  account  of  the  great  amount  of 
natural  heating  glass  surface,  the  temperature  soon  runs  up 
above  the  normal,  causing  a  necessity  for  opening  the  ven- 
tilators and  so  wasting  the  heat.  And  should  the  tempera- 
ture once  get  down,  it  takes  a  long  time  to  get  it  up  again. 

The  advantage  of  steam  in  this  case  is  apparent,  as  it  is 
capable  of  being  handled  nnd  regulated  rapidly,  and  there- 
fore is  superior  to  any  other  method  wherever  an  even  and 
uniform  temperature  is  desired  either  for  a  greenhouse  or  a 
dwelling. 

Comparative  Economy.—  Careful  experiments  have  recently 
been  made  by  parties  owning  many  greenhouses— some  of 
which  are  warmed  by  steam  and  others  by  the  most  approved 
of  hot-water  heaters— for  the  purpose  of  accurately  deter- 
mining the  relative  cost  of  fuel  in  each  case.  They  had 
nothing  to  gain  by  such  experiments  except  the  truth,  as, 
with  all  florists,  coal  is  a  very  heavy  item  and  one  of  the 
principal  expenses  attending  the  running  of  a  greenhouse. 

Without  entering  into  details,  it  has  been  demonstrated 
that  greenhouses  may  be  heated  by  steam  on  two-thirds  the 
quantity  of  coal  required  for  a  hot-water  apparatus.  This 
fact  has  become  so  well  established,  that  to-day  steam  is 
very  rapidly  taking  the  place  of  every  other  method  for 
warming  greenhouses. 

The  objections  to  hot  water  for  this  class  of  buildings  is, , 
moreover,  much  less  than  for  residences,  on  nearly  all  the 
preceding  five  points.  For  instance,  a  leakage  of  a  pipe  can 
do  no  harm,  as  in  a  house,  and  there  is,  of  course,  no  occa- 
sion to  shut  off  any  portion  of  the  system,  as  is  sometimes 
desired  in  a  house.  \- 

^Although  the  expense  of  a  change  from  hot  water  to  steam 
is  heavy,  yet  the  advantages  secured  are  so  great  and  ap- 
parent th?-t  it  will  not  be  long  before  hot  water  as  a  heating 
agent  will  be  practically  abandoned  in  every  kind  of  building. 


INTERESTING   FACTS  ABOUT  ISINGLASS. 

Isinglass  consists  of  the  dried  swimming  bladder  of  fishes. 
The  bladders  vary  in  shape,  according  to  their  origin,  and 
they  are  prepared  for  the  market  in  various  ways.  Some 
are  simply  dried  while  slightly  distended,  forming  pipe 
isinglass.  When  there  are  natural  openings  in  these  tubes 
they  are  called  pursers.  When  the  swimming  bladders  are 
slit  open,  flattened,  and  dried,  they  are  known  as  leaf  isin- 
glass. Other  things  being  equal,  the  value  of  a  sample  is 
determined  by  the  amount  of  impurities  present.  These  im- 
purities are  ordinary  dirt,  mucus  naturally  present  inside  the 
bladder  technically  called  grease,  and  blood  stains.  If  the 
bladderSp  were  hung  up  to  dry  with  the  orifice  downward,  the 
mucus  could  be  drained  off;  but  usually  the  fishermen  fear 
the  reduction  in  weight,  and  take  care  to  retain  all  they  can. 
It  is  necessary  to  insist  on  having  the  bladders  slit  up  and 
rinsed  clean  as  soon  as  they  are  removed  from  the  fish.  This 
would  so  much  increase  the  value  of  the  product  that  the 
extra  labor  would  be  very  profitable.  Blood  stains  cannot 
be  removed  without  injuring  the  quality.  If  any  process 
could  be  devised  effectual  for  this  purpose,  a  valuable  dis- 
covery would  be  made. 

The  uses  of  isinglass  are  not  very  varied.  The  largest 
quantity  is  used  by  brewers  and  wine  merchants  for  clarifying. 
This  property  is  extraordinary,  for  gelatin,  which  seems  chem- 
ically the  same  thing  as  isinglass,  does  not  possess  it. 

For  clarifying  purposes  the  isinglass  is  "  cut  "  or  dissolved 
in  acid,  sulphurous  acid  being  used  by  brewers,  as  it  tends  to 
preserve  the  beer.  When  reduced  to  the  right  consistence,  a 
little  is  placed  in  each  cask  before  sending  it  out  for  consump- 
tion. *$ 

There  seems  to  be  only  six  isinglass  cutters  in  England, 
all  being  in  London.  The  sorted  isinglass  is  very  hard  and 
difficult  to  manipulate.  It  is  soaked  till  it  becomes  a  little 
pliable,  and  is  then  trimmed.  Sometimes  it  is  just  pressed  by 
hand  on  a  board  Math  a  rounded  surface  ;  at  others  it  is  run  once 
between  strong  rollers  to  flatten  it  a  little.  The  next  process 
is  that  of  rolling.  Very  hard  steel  rollers,  powerful  and 
accurately  adjusted,  are  usedf  They  are  capable  of  exerting 
a  pressure  of  100  tons.  Two  areemployed,  the  first  to  bring  the 
isinglass  to  a  uniform  thickness,  and  the  smaller  ones,  kept  cool 
by  a  current  of  water  running  through  them  to  reduce  it  to 


466 

little  more  than  the  thickness  of  writing  paper.  From  the  finer 
rollers  it  comes  in  a  beautifully  transparent  ribbon,  many 
yards  to  the  pound,  "  shot "  like  watered  silk  in  parallel  lines 
about  an  inch  broad.  It  is  now  hung  up  to  dry  in  a  separate 
room,  the  drying  being  an  operation  of  considerable  nicety. 
When  sufficiently. dried,  it  is  stored  till  wanted  for  cutting,  or 
it  is  sold  as  ribbon  isinglass  to  all  who  prefer  this  form. 

MODERN  USES  OF  TIN. 

The  uses  of  tin  have  greatly  increased  during  the  last  few 
centuries  of  our  era.  Salmon,  in  his  splendid  work  on  casting 
tin  (1788),  describes  the  methods  of  work,  and  mentions  the 
objects  manufactured  from  this  metal.  We  see  from  the 
plates  of  his  atlas  that  table  services  (spoons  and  forks) 
pitchers,  jugs,  candelabra,  lamps,  surgical  instruments,  chem- 
ical apparatus,  boilers  for  dyeing  scarlet,  etc.,  were  being  put 
upon  the  market  in  the  most  varied  forms  of  that  epoch. 

Griffith,  between  1840  and  1850,  perfected  the  manufacture 
of  tin  utensils  in  a  single  piece.  This  industry  became  espe- 
cially developed  in  France  from  1850  to  1860. 

In  1860  America  began  manufacturing  impermeable  boxes, 
without  soldering,  from  single  pieces  of  metal.  &> 

%  To-day  tin  is  being  used  in  the  manufacture  of  bronzes  for 
guns,  money  and  medals,  and  in  the  alloys  used  for  making 
measures  of  capacity  for  liquids.  Its  unalterability  in  the  air, 
and  the  harmlessness  of  its  salts  when  they  exist  in  small 
quantity,  cause  it  to  be  employed  in  our  day  in  the  manufac- 
ture of  culinary  vessels  and  utensils.  Advantage  is  taken  of 
its  malleability  to  form  from  it  those  tbm  sheets  that  are 
used  as  wrappers  for  chocolate,  tea,  etc. 

In  the  various  bronzes  that  it  forms  with  copper,  we  have 
evidence  of  the  influence  that  relative  proportions  of  the  two 
metals  have  upon  the  properties  of  the  alloy.  Thus  gun  bronze, 
which  contains  ten  parts  of  tin  to  ninety  of  copper,  is  remark- 
able  for  tenacity.  The  bronze  of  tom-toms  and  bells,  which 
differs  from  the  last  named  only  in  its  larger  proportion  of 
tin  (twenty  to  eighty  of  copper)  is,  on  the  contrary,  very  brit- 
tle, although  it  fortunately  possesses  greater  sonorousness 
than  gun  metal  does.  On  still  further  increasing  the  propor- 
tion of  tin  to  thirty-throe  parts  per  sixty-seven  of  copper,  we 
obtain  a  white  alloy  capable  of  taking  a  polish  that  causes  it 
to  be  used  for  the  manufacture  of  telescope  mirrors.  Upon 
uniting  with  tin,  copper  loses  its  ductility.  The  alloys  of 
these  two  metals  increase  in  density  through  being  hardened, 
as  th^y  do  also  by  being  hammered. 


467 

A  mixture  of  twenty  parts  of  tin  with  eighty  of  copper 
gives  an  alloy  which  is  brittle  at  a  bright  red  heat  and  when 
cold,  but  wnich  is  malleable  at  a  dark  red  heat. 

When  alloyed  with  lead,  the  tin  forms  plumbers'  solder. 
Associated  with  mercury,  it  gives  the  silvering  of  looking- 
glasses.  Besides  this,  it  enters  into  a  host  of  fusible  alloys  or 
compositions,  known  under  the  general  name  of  white  metal. 
One  of  these  alloys,  composed  of  tin,  antimony  and  copper, 
is  very  much  used  as  a  bushing  for  engine  bearings.  For  this 
purpose  the  following  are  very  good  proportions:  Tin,  100; 
antimony,  10  ;  copper,  10.  It  is  also  alloyed  with  antimony 
alone,  or  with  bismuth.  It  serves  for  tinning  copper  and  iron 
kitchen  utensils.  To  this  effect  the  wrought-iron  utensils 
are  cleaned  with  sand  and  then  wiped,  and  afterward  im- 
mersed in  a  bath  of  molten  tin,  and  finally  rubbed  with  tow 
saturated  with  sal-ammoniac.  Food  cooked  in  tin  vessels  has 
a  slight  fishy  taste,  because  it  dissolves  a  little  of  the  tin,  just 
as  food  prepared  in  iron  contracts  a  slight  taste  of  ink. 

Tin  is  used  in  enormous  quantities  also  in  the  manufacture 
of  tinplate.  In  order  to  prepare  this,  the  sheet  iron  designed 
for  the  manufacture  of  it  is  cleansed  by  plunging  into  diluted 
mlphuric  acid,  which  dissolves  the  pellicles  of  oxide.  Then 
it  is  rubbed  with  sand  and  immersed  in  melted  tallow,  and 
afterward  in  a  bath  of  tin  covered  with  tallow.  When  taken 
out  it  is  tinned,  there  having  formed  upon  the  surface  of  the 
sheet  iron  a  true  alloy  of  iron  and  tin  covered  with  pure  tin. 
Tin  plate  is  as  unalterable  a*s  tin  itself,  because  the  iron  does 
not  come  into  contact  with  the  air  at  any  point;  but  if,  upon 
cutting  it,  we  expose  the  iron,  oxidation  proceeds  more  rapidly 
than  it  would  if  the  iron  had  not  been  tinned. 

Upon  washing  the  surface  of  the  tinplate  with  a  mixture 
of  hydrochloric  and  nitric  acids,  we  remove  the  superficial 
layer,"and  render  visible  the  crystallized  surface  of  the  tin  and 
iron  alloy.  We  thus  obtain  what  is  called  moire  metallic  or 
crystallized  tinplate. 

It  now  remains  for  us  to  say  a  few  words  about  the  new 
and  important  use  of  tin  for  the  preparation  of  phosphor 
bronze. 

In  the  melting  of  bronze  the  absorption  of  oxygen  is 
very  detrimental,  the  formation  of  an  oxide  of  tin  rendering 
the  metal  brittle.  In  former  times  an  endeavor  was  made  to 
prevent  this  oxidation  by  stirring  the  mass  with  wood,  or  by 
adding  a  little  zinc  to  it  ;  but  for  the  last  fifteen  years 
greater  success  has  been  obtained  by  the  addition  of  a  little 
phosphorus  This  substance  extraordinarily  increases  the 
compactness,  toughness  and  elasticity  of  the  product,  and 


468 

gives  it,  in  addition,  a  beautiful  golden  color.  Guns, 
statues,  ornaments  and  bearings  are  now  cast  from  phosphor 
bronze  with  the  greatest  success. 

Kunzel,  of  Dresden,  has  taken  out  a  patent  for  an  alloy 
composed  one-half  to  three  parts,  by  weight,  of  phosphorus, 
from  four  to  fifteen  of  lead,  from  four  to  fifteen  of  tin,  and 
for  the  rest,  copper  up  to  100. 

Schiller  &  Sewald,  of  Graupen,  prepare  two  kinds  of 
phosphor  brojze;  one  with  2>^  and  the  other  5  per  cent,  of 
phospnorus.  The  demand  for  this  article  is  daily  becoming 
more  extensive. 

The  most  important  uses  of  tin  are,  in  Asia,  for  tinning 
copper,  and  in  Europe  and  America,  for  the  manufacture  of 
objects  from  tinplate.  The  manufacture  of  bronze  and 
white  metal  likewise  consumes  a  large  quantity. 

USES    OF   MICA. 

The  peculiar  physical  characteristics  of  mica,  its  resistance 
to  heat,  transparency,  capacity  of  flexure  and  high  electric 
resistance,  adapt  it  to  applications  for  which  there  does  not 
appear  tc  be  any  perfect  substitute.  Its  use  in  windows, 
in  tKe  peep-holes  on  the  furnaces  used  in  metallurgical  pro- 
cesses, as  well  as  the  ordinary  use  in  stoves  for  domestic  pur- 
poses, are  examples  of  its  adaptability  to  specific  purposes 
which  it  does  not  seem  to  share  with  any  other  material.  Its 
fitness  for  use  in  physical  apparatus  is  represented  by  its 
application  for  the  vanes  on  the  Coulomb  meter,  recently  in- 
vented by  Prof.  George  Forbes,  F.  R.  S.  For  electrical 
purposes  mica  has  proved  useful,  acting  as  an  insulator  be- 
tween the  segments  of  commutators  of  dynamos  and  safety 
fuses  in  lighting  circuits,  also  as  the  base  part  of  switches 
handling  heavy  currents,  to  obviate  the  dangers  of  ignition 
by  the  arc  formed  when  the  switch  is  changed.  For  this 
latter  purpose  it  shares  the  field  with  sheets  of  slate.  Both 
of  these  uses  were  first  suggested  a  number  of  years  ago  by  an 
insurance  expert  in  America  in  the  course  of  regulations  gov- 
erning the  safe  installation  of  electric-light  plants.  As  a 
lubricator,  mica  answers  a  veiy  peculiar  purpose  for  classes 
of  heavy  bearing,  where  the  powdered  mica  serves  a  useful 
office  in  keeping  the  surface  separate,  thereby  permitting  the 
free  ingress  of  oil.  It  is  used  in  roof-covering  mixtures  in  a 
powdered  condition  in  combination  with  coal  tar,  ground 
steatite  and  other  materials,  its  foliated  structure  tending  to 
bond  the  material  together.  Not  affected  by  ordinary  chem- 
icals which  are  corrosive  to  many  other  substances,  it  has 


469 

been  applied  in  the  valves  to  sensitive  automatic  sprinklers, 
where  a  sheet  of  mica  placed  over  a  leather  disk  has  proved 
to  be  non-corrosive,  and  without  possibility  of  adhering  to 
the  seat,  while  the  leather  packing  rendered  the  whole  suffi- 
ciently elastic  to  provide  a  tight  joint. 

IMPROVED  PROCESS  OF  TINNING. 

An  improved  process  of  coating  metals  with  tin,  by  Borthel 
and  Holler,  of  Hamburg,  is  said  (by  a  metropolitan  contem- 
porary) to  possess  the  advantage  of  preventing,  or  at  least 
delaying,  oxidation.  The  process  can  be  employed  with 
special  advantage  for  tinning  cast-iron  cooking  utensils, 
household  and  other  implements  of  cast  iron,  as  the  employ- 
ment of  poisonous  enamel  is  avoided  and  a  much  higher 
degree  of  polish  attained.  The  process  can  also  be  employed 
for  protecting  architectural  or  other  iron  decorations  from 
rusting  by  the  coating  of  tin  or  other  metal,  without  detri- 
ment to  the  sharpness  of  the  form,  as  is  the  case  with  the 
customary  oil  or  bronze  paints.  In  order  to  produce  a  per- 
fectly even  coating  of  tin  on  cast  iron,  the  same  is  first  provided 
with  a  thin  coating  of  chemically  pure  iron,  regardless  of  the 
form  of  casting.  This  coating  is  produced  in  galvanic  man- 
ner in  a  bath  composed  as  follows :  Six  hundred  grammes 
of  sulphate  of  iron,  FeSO4,  are  dissolved  in  five  liters  of  water, 
to  which  add  a  solution  of  about  2,400  grammes  of  carbonate 
of  soda,  Na2CO3,  in  five  liters  of  water.  The  precipitate  of 
ferro-carbonate  (FeCo3)  resulting  is  dissolved  in  small  quan- 
tities in  so  much  concentrated  sulphuric  acid  until  the  fluid 
has  a  green  color.  The  bath  is  then  rendered  aqueous  by 
adding  about  twenty  liters  of  water.  Blue  litmus  paper 
dipped  in  the  bath  must  assume  a  deep  claret  color,  and  red 
litmus  paper  remains  unchanged. 

>  The  objects  to  be  provided  with  a  coating  of  chemically 
pure  iron  are  placed  in  the  bath  opposite  to  the  abode  of  cast 
or  wrought  iron  or  iron  ore,  and  both  parts  connected  to  the 
Corresponding  poles  of  a  dynamo  machine,  electric  battery,  or 
other  appropriate  source  of  electricity.  In  a  very  short  time 
the  objects  placed  in  the  bath  are  covered  with  a  coating  of 
iron,  the  thickness  of  which  depended  on  the  duration  of  the 
action  of  the  bath  or  the  strength  of  electric  mrrent.  $  The 
Coated  objects  are  then  well  rinsed  in  clear  wat  /r,  dried,  then 
painted  with,  or  immersed  in,  a  solution  c-f  ammonia  in 
chloride  of  zinc  alone,  and  then  immersed  v*  a  vessel  contain- 
ing molten  tin  The  tin  adheres  with  g>Vat  tenacity  to  the 
prepared  surface,  and  the  surplus  of  tin  '/an  be  readily  removed 


470 

by  a  brush,  or  any  other  manner.  If  the  object  to  be  tinned 
is  of  such  size,  or  so  complicated  in  form,  that  it  cannot  be 
readily  immersed  in  molten  tin,  it  can  be  placed  in  a  galvanic 
tin  bath,  which  can  be  readily  made  in  any  desired  size,  and 
be  provided  with  a  layer  of  tin  of  desired  thickness,  which, 
after  having  been  painted  either  with  a  solution  of  chloride  of 
zinc  or  ammonia  in  chloride  of  zinc,  can  be  heated  to  such  a 
degree  that  the  tin  is  equally  melted  on  the  object. 

In  like  manner  objects  cast  or  made  of  lead  or  other 
readily  melting  metal,  which  would  lose  their  form  by  melt- 
ing when  immersed  in  molten  tin,  are,  previous  to  tinning, 
provided  with  a  coating  of  pure  iron,  and  are  then  provided 
with  a  coating  of  tin  in  a  galvanic  bath,  as  mentioned  above, 
without  being  subjected  to  heat  for  melting  the  layer  of  tin 
deposited  on  the  same.  With  objects  of  wrought  or  rolled 
iron,  or  which  clo  not  require  the  before  described  treatment 
—  id  est,  the  production  of  a  coating  of  chemically  pure 
iron  —  it  will  be  sufficient  to  carefully  clean  the  same  and 
paint  them  with  a  solution  of  ammonia  or  chloride  of  zinc 
or  a  concentrated  solution  of  chloride  of  zinc.  This  tinning 
process  combines  the  advantage  of  simple  manipulation  and 
the  great  durability  of  the  coating  with  cheapness  of  manu- 
facture, which  is  partially  attained  in  the  saving  of  tin. 

SOLDERING. 

The  term  soldering  is  generally  applied  when  fusible 
alloys  of  lead  and  tin  are  employed  for  uniting  metals. 
When  hard  metals  which  melt  only  above  a  red  heat,  such 
as  copper,  brass  or  silver,  are  used,  the  term  brazing  is  some- 
times used.  Hard-soldering  is  the  art  of  soldering  or  uniting 
two  metals  or  two  pieces  of  the  same  metal  together  by 
means  of  a  solder  that  is  almost  as  hard  and  infusible  as  the 
metals  to  be  united.  In  some  cases  the  metals  to  be  united 
a»e  heated,  and  their  surface  united  without  solder  by  flux- 
ing the  surfaces  of  the  metals.  This  process  is  then  termed 
burning  together.  Some  of  the  hard-soldering  processes  are 
often  termed  brazing.  Both  brazing  and  hard-soldering  is 
usually  done  in  the  open  fire  on  the  brazier's  hearth."*^  A 
soldered  joint  is  more  perfect  and  more  tenacious  as  the 
point  of  the  fusion  of  the  solder  rises.  Thus,  tin,  which 
greatly  increases  the  fusibility  of  its  alloys,  should  not  be 
used  for  solders,  except  when  a  very  easy-running  solder  is 
wanted.  Solders  made  with  tin  are  not  so  malleable  and 
tenacious  as  those  prepared  without  it.  The  Egyptians  sol- 
dered with  lead  as  long  ago  as  B.  C.  1490,  the  time  of  Moses. 


Pliny  refers  to  the  art,  and  says  it  requires  the  addition  of 
tin  to  use  as  a  solder.  The  tin  came  mainly  from  the  Cas- 
siterides  (Cornwall).  Plumbers  use  solder  composed  of  two 
parts  of  lead  and  one  of  tin,  and  a  very  slight  variation  in 
the  quantities  makes  a  very  considerable  difference  in  the 
working  and  also  in  the  soundness  of  the  joint.  If  a  slight 
excess  over  the  above  proportion  of  lead  is  used,  the  soldef 
is  more  difficult  to  work,  and  the  joint  when  made  fre- 
quently leaks,  the  water  passing  through  the  small  cellules  o* 
pores  in  the  metal,  and  the  joint  is  then  said  to  "  sweat."  If 
an  excess  of  tin  is  used,  the  solder  melts  too  easily,  and  con« 
siderable  difficulty  is  found  in  keeping  it  on  the  joint,  and  it 
cools  so  suddenly  that  the  joints  always  look  rough  and 
ragged  at  the  ends.  They  sometimes  require  trimming  up  to 
make  them  look  better  ;  this  solder  also  keeps  running,  an<? 
then  congealing,  in  such  a  way  as  to  be  difficult  to  keep 
it  at  a  workable  heat  Small  portions  of  the  metal  also 
keep  sticking  to  the  cioth  used  for  molding  (technically 
called  wiping)  the  joint  or  seam  as  the  case  may  be. 

Plumbers'  solder,  with  the  above  proportions,  on  being 
melted,  and  then  allowed  to  cool,  will  generally  exhibit  sev- 
eral bright  spots  on  its  surface,  due  to  the  two  metals  partly 
separating.  These  bright  spots  are  generally  a  very  sure 
guide  as  to  the  proper  quantities  of  each  metal  used.  If 
none  are  seen,  it  is  too  coarse;  and  if  too  many  are  seen,  it 
contains  too  much  tin  and  is  said  to  be  too  fine.  If  the  spots 
are  small  the  metal  may  not  be  good,  although  it  may  have 
beyond  its  proper  quantity  of  tin;  but  if  the  spots  are  about 
the  size  of  a  threepenny  piece  the  solder  very  rarely  fails  to 
work  well.  In  uniting  tin,  copper,  brass,  etc.,  with  any  of 
the  soft  solders  a  copper  soldering-bit  is  generally  used.  This 
tool  and  the  manner  of  using  it  are  well  known.  In 
many  cases  the  work  may  be  done  more  neatly  without  the 
soldering-bit  by  filing  or  turning  the  joints  so  that  they  fit 
closely,  moistening  them  with  the  soldering  fluid  described 
hereafter,  placing  a  piece  of  smooth  tin  foil  between  them, 
tying  them  together  with  binding  wire,  and  heating  the 
whole  in  a  lamp  or  fire  till  the  tin  foil  melts.  Pieces  of  brass 
are  often  joined  in  this  way  so  that  the  joints  are  invisible. 
With  good  soft  solder  almost  any  work  may  be  done  over  a 
spirit  lamp,  or  even  a  candle,  without  the  use  of  a  soldering- 
bit.  Advantage  may  be  taken  of  the  varying  degrees  of 
fusibility  of  solders  to  make  several  joints  in  the  same  piece 
of  work.  %•  Thus,  if  the  first  joint  has  been  made  with  the 
fine  tinners'  solder,  there  would  be  .no  dangej^pf  melting  it 
in  making  a  ioint  near  it  with  bismuth  solder:  The  fusibil- 


472 

jty  of  soft  solder  is  increased  by  adding  msmuth  to  the  com- 
position. An  alloy  of  lead  4  parts,  tin  4  parts,  and  bismuth 
i  part,  is  easily  melted;  but  this  alloy  may  itself  be  soldered 
with  an  alloy  of  lead  2  parts,  bismuth  2  parts,  and  tin  r  part. 
By  adding  mercury  a  still  more  fusible  solder  can  be  made. 
Equal  parts  of  lead,bismuth  and  mercury,  with  two  parts  of 
tin,  will  make  a  composition  which  melts  at  122  degrees 
Fahr. ;  or  an  alloy  of  .tin  5  parts,  lead  3  parts,  and  bismuth 
3  parts,  will  melt  in  boiling  water.  In  melting  these  solders 
melt  the  least  fusible  metal  first  in  an  iron  ladle,  then  add  the 
others  in  accordance  with  their  infusibility.  It  is  convenient 
—  and  in  fact,  often  necessary  —  to  hare  solders  which  will 
melt  at  different  degrees  of  temperature,  to  avoid  the  risk  of 
spoiling  the  work  by  subjecting  it  to  too  great  a  heat,  when, 
with  a  little  easy-flowing  solder,  there  would  be  no  danger. 

POINTS  ON  SOLDERING. 

For  tinning  soldering  coppers  nothing  is  bettev  than  a 
soft -burned  brick  to  contain  the  tin  and  solder.  Dig  a  cavity 
on  the  side  two  or  three  inches  long,  and  wide  enough  to 
receive  the  soldering  tool.  Melt  some  solder  in  the  cavity  thus 
formed,  and  throw  in  some  pieces  of  sal-ammoniac  and  rosin. 
See  that  the  copper  bits  are  hot  enough  to  melt  solder ;  a 
great  heat  will  not  tin  as  well  as  a  low  one.  Rub  the  tool 
om  the  brick,  melting  the  solder,  ammoniac  and  rosin.  The 
trick  scours  the  copper  bright,  and  the  flux  causes  the  solder 
to  adhere  very  easily.  One  of  the  worst  things  ever 
attempted  is  to  solder  a  dirty  job  with  a  dirty,  untinned 
copper. 

See  that  the  surfaces  to  be  soldered  are  clean.  If  not, 
make  them  so  by  filing  or  scraping  ;  then  protect  the  surfaces 
from  oxidation  by  an  application  of  flux  or  muriatic  acid  in 
which  zinc  has  been  dissolved.  Have  the  soldering  copper 
hot.  Hold  it  two  inches  from  your  face,  and  the  right 
degree  of  heat  will  soon  be  learned.  When  all  of  these 
conditions  exist,  the  melted  solder  will  flow  along  the  seam 
with  the  greatest  ease,  leaving  a  smooth,  well-finished  surface 
behind  it.  •*  > 

To  do  work  in  the  best  manner  and  the  easiest,  a  flux 
should  be  provided  for  each  metal  to  be  soldered.  The 
hydrochloric  (muriatic)  acid  and  zinc  flux  is  worthless  when 
rust  is  to  be  avoided,  for  in  some  cases  the  acid  continues 
to  act  after  the  soldering  is  done,  and  in  a  few  months  may 
eat  far  enough  to  separate  the  solder  from  the  work,  la 
this  case,  of  course,  the  joint  falls  apart. 


473 

In  soldering  zinc  some  use  muriatic  acid  diluted  with 
water  for  a  flux,  and  the  rusting  action  is  to  be  feared  in 
this  instance,  but  may  be  lessened  by  adding  soda  carbonate 
(washing  soda)  to  the  acid.  There  are  few  pieces  that  can- 
not be  soldered  without  the  use  of  an  acid  flux,  and  rosin 
will  do  nearly  as  well  if  a  little  oil  be  added,  or  if  the  solder- 
ing copper  be  dipped  in  acid  and  then  into  oil  before  apply- 
ing it  to  the  seam  with  rosin  on  it. 

Sal-ammoniac  is  the  proper  flux  for  copper,  and  this 
agent  works  well  with  tin,  but  it  is  not  necessary,  for  rosin 
is  all  that  is  needed.  Lead  is  perfectly  fluxed  by  tallow  (the 
plumbers  call  it  "  touch  "),  but  may  be  soldered  with  either 
of  the  other  fluxes. 

NEW  METHOD  OF  BRONZING   IRON. 

The  following  method  is  successful  in  producing  a  bronze- 
like  surface  which  practically  prevents  rust.  All  the 
methods  as  yet  known  for  producing  a  bronze-like  surface,  by 
rubbing  over  the  surface  of  the  iron  an  acid  solution  of  cop- 
per or  an  iron  solution,  letting  it  dry  in  the  air,  brushing  off 
the  rust  produced  in  this  way,  and  an  abundant  repetition  of 
this  method,  give  a  more  or  less  reddish-brown  crust  or  rust 
on  the  iron  body.  Objects  formed  of  iron  can  easily  be 
covered  with  copper  or  brass  by  dipping  them  in  the  requisite 
solution,  or  by  submitting  them  to  the  galvanic  method.  The 
surface  so  prepared,  however,  peels  off  in  a  short  time,  by 
exposure  to  moist  ajr  in  particular.  By  the  method  given 
below  it  is  possible  to  cover  iron  objects,  especially  such  as 
have  an  artistic  aim,  with  a  fine  bronze-like  surface  ;  it  resists 
pretty  satisfactorily  the.  influence  of  moisture,  and  one  is, 
moreover,  enabled  to  apply  it  to  any  object  with  great  ease. 
The  clean,  polished  objects  are  to  be  exposed  to  the  action  of 
the  vapors  of  a  heated  mixture  of  hydrochloric  acid  and 
nitric  acid,  in  equal  portions,  for  from  two  to  five  minutes; 
they  are  not  to  be  shifted,  and  the  temperature  may  range 
from  300°  to  350°  C.  The  heating  is  continued  so  long  that 
the  bronze-like  surface  is  well  developed  on  the  surface  of  the 
objects.  After  the  objects  have  cooled  they  should  be 
well  ruboed  down  with  vaseline  and  again  heated  until  the 
vaseline  begins  to  decompose.  When  again  cold  they  should 
be  a  second  time  treated  with  vaseline  in  the  same  way.  If 
the  vapor  of  a  mixture  of  the  twro  concentrated  acias  is 
allowed  to  act  on  an  iron  object  in  this  manner,  a  light  red- 
dish-brown tone  is  developed.  If  some  acetic  acid  be  mixed 
with  the  two  acids,  and  the  vapor  of  all  the  acids  together  be 


474 

allowed  to  act  On  the  metallic  surface,  a  fine  bronze  yellow 
color  can  be  obtained.  By  using  different  mixtures  of  these 
acids  every  tint,  from  a  dull  red-brown  to  a  light  brown,  and 
from  a  dull  brownish  yellow  to  light  brown  yellow,  can  be 
produced  on  the  surface  of  the  iron.  In  this  way  some 
T-rods  for  iron  boxes  were  covered  with  a  bronze-like  surface, 
and  at  the  end  of  ten  months,  although  exposed  during  the 
whole  time  to  the  action  of  the  acid  fumes  of  a  *  bnratory, 
they  had  undergone  no  trace  of  any  change. 

MAN  JFACTURE  OF   RUSSIAN  SHEET  IRON. 

There  appears  to  be  much  misunderstanding  in  reference 
to  the  manufacture  of  sheet  iron  in  Russia,  and  questions 
are  frequently  asked  the  writer  :  "  What  are  the  secrets  con- 
nected with  it  ?  "  "  How  is  it  made  ?  "  "  Could  admission  be 
obtained  to  the  iron  works  in  the  Urals,  where  the  iron  is 
made?"  It  is  difficult  to  understand  why  such  questions 
should  be  asked  by  persons  versed  in  the  literature  of 
iron  and  steel,  for  Dr.  Percy  wrote  a  very  excellent  and 
accurate  monograph  on  the  subject  a  number  of  years  ago. 

Not  having  had  the  opportunity  of  personally  visiting  the 
Russian  iron  works  in  the  Urals,  Dr.  Percy's  paper  was  com- 
piled from  data  furnished  him  by  a  number  of  persons  who 
had  actually  visited  these  sheet  iron  works.  Since  it  has 
been  my  good  fortune  to  have  the  opportunity  of  seeing 
some  of  these  works  in  the  Urals,  but  a  short  time  ago,  I 
will,  at  the  risk  of  telling  an  old  story,  briefly  describe  the 
process  of  manufacture  as  I  saw  it. 

The  ores  used  for  the  manufacture  of  this  iron  are  mostly 
from  the  celebrated  mines  of  Maloblagodatj,  and  average 
about  the  following  chemical  composition:  Metallic  iron, 
60  per  cent. ;  silica,  5  per  cent. ;  phosphorus  from  o.  15  to  0.06 
per  cent.  The  ore  is  generally  smelted  into  charcoal  pig 
iron,  and  then  converted  into  malleable  iron  by  puddling  or 
by  a  Franche-Comte  hearth.  Frequently,  however,  the 
malleable  iron  is  made  directly  from  the  ore  to  various  kinds 
of  bloomaries. 

The  blooms  or  billets  thus  obtained  are  rolled  into  bars  6 
inches  wide,  %  inch  thick  and  30  inches  in  length.  These 
bars  are  assorted,  the  inferior  ones  "  piled "  and  re-rolled, 
while  the  others  are  carefully  heated  to  redness  and  cross- 
rolled  into  sheets  about  thirty  inches  square,  requiring  from 
eight  to  ten  passes  through  the  rolls.  These  sheets  are  twice 
again  heated  to  redness,  and  rolled  in  sets  of  three  each,  care 
being  taken  th  t  every  sheet  before  being  pas?ed  through  the 


475 

rolls  is  brushed  off  with  a  wet  broom  made  of  fir,  and  at  the 
same  time  that  powdered  charcoal  is  dextrously  sprinkled 
between  the  sheets.  Ten  passes  are  thus  made,  and  the 
resulting  sheets  trimmed  to  a  standard  size  of  twenty-five  to 
fifty-six  inches.  After  being  sorted  and  the  defective  ones 
thrown  out,  each  sheet  is  wetted  with  water,  dusted  with 
charcoal  powder  and  dried.  They  are  then  made  into  pack- 
ets containing  from  sixty  to  one  hundred,  and  bound  up  with 
waste  sheets. 

The  packets  are  placed  one  at  a  time,  with  a  log  of  wood 
at  each  of  the  four  sides,  in  a  nearly  air-tight  chamber,  and 
carefully  annealed  for  five  or  six  hours.  When  this  has  been 
completed  the  packet  is  removed  and  hammered  with  a  trip- 
hammer weighing  about  a  ton,  the  area  of  its  striking  surface 
being  about  six  to  fourteen  inches.  The  face  of  the  hammer 
is  made  of  this  somewhat  unusual  shape  in  order  to  secure  a 
wavy  appearance  on  the  surface  of  the  packet.  After  the 
packet  has  received  ninety  blows,  equally  distributed  over  its 
surface,  it  is  reheated  and  the  hammering  repeated  in  the 
same  manner.  Sometime  after  the  first  hammering  the  packet 
is  broken  and  the  sheets  wetted  with  a  mop,  to  harden  the 
surface.  After  the  second  hammering  the  packet  is  broken, 
the  sheets  examined,  to  ascertain  if  any  are  welded  together, 
and  completely  finished  cold  sheets  are  placed  alternately 
between  those  of  the  packet,  thus  making  a  large  packet  of 
from  140  to  200  sheets.  It  is  supposed  that  the  interposition 
of  these  cold  sheets  produces  the  peculiar  greenish  color  that 
the  finished  sheets  possess  on  cooling. 

This  large  packet  is  then  given  what  is  known  as  the 
finishing  or  polishing  hammer  ing.  For  this  purpose  the  trip- 
hammer used  has  a  larger  face  than  the  others,  haying  an 
area  of  about  17  to  21  inches.  When  the  hammering  has 
been  properly  done  the  packet  has  received  60  blows,  equally 
distributed,  and  the  sheets  should  have  a  perfectly  smooth, 
mirror-like  surface.  The  packet  is  now  broken  before  cool- 
ing, each  sheet  cleaned  with  a  wet  fir  broom  to  remove  the 
remaining  charcoal  powder,  carefully  inspected,  and  the  good 
sheets  stood  on  their  edges  in  vertical  racks,  to  cool.  These 
sheets  are  trimmed  to  regulation  size  (28  by  56  inches)  and 
assorted  into  Nos.  i,  2  and  3,  according  to  their  appearance, 
and  again  assorted  according  to  weight,  which  varies  from 
10  to  12  Ibs.  per  sheet.  The  quality  varies  according  to  color 
and  freedom  from  flaws  or  spots.  A  first-class  sheet  must  be 
without  the  slightest  flaw,  and  have  a  peculiar  metallic  gray 
color,  and  on  bending  a  number  of  times  with  the  fingers, 
very  little  or  no  scale  is  separated,  as  in  the  case  of 


476 

ordinary  sheet  iron.  The  peculiar  property  or  Russian  sheet 
iron  is  the  beautiful  polished  coating  of  oxides  ( '  glanz") 
which  it  possesses.  If  there  is  any  secret  in  the  process,  it 
probably  lies  in  the  "  trick  "  of  giving  this  polish.  As  far  as  I 
was  able  to  judge,  from  personal  observation  and  conversa- 
tion with  the  Russian  iron  masters,  the  excellence  of  this 
sheet  iron  appeared  to  be  due  to  no  secret,  but  to  a  variety  of 
conditions  peculiar  to  and  nearly  always  present  in  the 
Russian  iron  works  of  the  Urals.  Besides  the  few  partic- 
ulars already  noted  in  the  above  description  of  this  process,  it 
should  be  borne  in  mind  that  the  iron  ores  of  the  Urals  are 
particularly  pure,  and  that  the  fuel  used  is  exclusively  char- 
coal and  wood.  Another  and  equally  important  considera- 
tion lies  in  the  fact  that  this  same  process  of  manufacturing 
sheet  iron  has  been  carried  on  in  the  Urals  for  the  last  hun- 
dred years.  As  a  consequence,  the  workmen  have  acquired  a 
peculiar  skill,  the  want  of  which  has  made  attempts  to  manu- 
facture equally  as  good  iron  outside  of  Russia  generally 
unsuccessful.  It  is  difficult  to  understand  what  effect  the  use 
of  charcoal  powder  between  the  sheets,  as  they  are  rolled  and 
hammered,  has  upon  the  quality.  It  is  equally  as  difficult  to 
understand  the  effect  of  the  interposition  of  the  cold-finished 
sheets  upon  the  production  of  the  polished  coating  of  oxide. 
The  Russian  iron-masters  seem  to  attribute  the  excellence  of 
their  rroduct  more  to  this  peculiar  treatment  than  to  any 
other  cause.  One  thing  is 'quite  certain,  there  is  no  secret 
about  the  process,  and  if  the  Russian  sheet  iron  is  so  much 
superior  to  any  other,  it  is  due  to  the  combination  of  causes 
already  indicated. 

THE     LARGEST    ELECTRIC    LIGHT    IN    THE 
WORLD. 

The  largest  electric  light  in  the  world  is  on  St.  Catharine's 
Point  lighthouse,  Isle  of  Wight.  Some  idea  of  the  power  of 
this  light  will  be  conveyed  when  it  is  known  that  the  carbons 
employed  in  electric  arc  lamps  commonly  used  for  street 
lighting  are  about  ^  inch  in  thickness,  while  these  have  a 
diameter  of  nearly  2^  inches. 

There  are  two  dynamos,  and  if  both  worked  in  conjunc- 
tion it  is  computed  that  the  concentrated  light  from  the 
lantern  would  equal  six  millions  of  candles.  The  induction 
arrangement  of  each  machine  consists  of  sixty  permanent 
magnets,  and  each  magnet  is  made  up  of  eight  steel  plates.  The 
armature,  2  ft.  6  in.  in  diameter,  is  composed  of  five  rings  with 
twenty-four  bobbins  in  each,  arranged  in  groups  of  four  in 
tension  and  six  in  quantity. 


477 


LUMBER  MEASUREMENT  TABLE. 


LENGTH 

LENGTH 

LENGTH 

LENGTH 

LENGTH 

LENGTH 

2X4 

2x6 

2x8 

2XIO 

3X6 

3*8 

12     8 

12   12 

12   l6 

12    20 

12    18 

12    24 

14   9 

14   14 

14  19 

H    23 

14    21 

14    28 

16   ii 

16  16 

16  21 

16   27 

16   24 

16   32 

18  .  12 

18  18 

18  24 

18   30 

18   27 

18   36 

20    13 

20   20 

20   27 

20   33 

20    30 

20    40 

22    15 

22   22 

22   29 

22   37 

22   33 

22   44 

24    ID 
26    17 

24   24 
26   26 

24   32 

26  35 

24  40 

26   43 

24  36 

20   39 

24    48 
26    52 

3\IO 

3X12 

4x4 

4x6 

4x8 

6x6 

12    30 

12   36 

12   l6 

12    24 

12    32 

12    36 

H   35 

14   42 

14  19 

14    28 

H   37 

14  42 

16   40 

16  48 

16  21 

16   32 

16   43 

16   48 

18   45 

18  54 

18  24 

1  8   36 

18   48 

18   54 

20    50 

20   60 

20   27 

20    40 

20   53 

20    60 

22   55 

22   66 

22   29 

22   44 

22   59 

22    66 

24   60 

24   72 

24   32 

24  48 

24   64 

24   72 

26  65 

26   78 

26  35 

26  52 

26   69 

26  78 

6x8 

8x8 

8xio 

IOXIO 

10X12 

12X12 

12    48 

12   64 

12   80 

12   100 

12   120 

12   144 

H   56 

H  75 

H  93 

14   117 

14   140 

14  168 

16   64 

16  85 

16  107 

16  133 

16  160 

16  192 

18   72 

18  96 

18  120 

18  150 

18  180 

18  216 

20   80 

20  107 

20  133 

20   167 

20   2OO 

20   240 

22    88 

22  117 

22  147 

22   183 

22   220 

22   264 

24  96 

24  128 

24  1  60 

24   200 

24   240 

24   288 

26  104 

26  139 

26  173 

26   217 

26   260 

26   312 

A  blast  at  800  degrees  temperature  will  ignite  charcoal ; 
900  degrees  will  ignite  coke,  and  1,300  degrees  will  ignite 
anthracite. 


478 
THE  DYNAMO. 

HOW  MADE  AND    HOW   USED. 

The  interest  awakened  in  machines  for  the  generation  of 
current  electricity,  consequent  upon  the  demand  for  electric 
lighting  and  transmission  of  power,  has  induced  many 
amateurs  to  turn  their  energies  to  the  construction  of  small 
dynamos,  such  as  might  replace  a  battery  of  eight  or  ten 
cells,  without  the  disagreeable  features  of  changing  acids, 
cleaning  plates,  etc.  Such  efforts  have  not  generally  met 
with  success,  owing  to  the  fact  that  no  work  of  a  practical  nat- 
ure has  yet  appeared  in  which  the  construction  of  the 
dynamo  is  fully  explained.  When  the  principles  which  con- 
trol the  manufacture  of  such  machines  is  understood, 
dynamos  can  be  constructed  with  as  much  ease  and  cer- 
tainty as  induction  coils. 

§  i.  What  a  Dynamo  is. — As  understood  at  present,  the 
dynamo-electric  machine  may  be  defined  as  a  machine 
whereby  energy  (motion)  is  converted  into  electricty  by  the 
aid  of  the  permanent  magnetism  present  in  certain  iron  por- 
tions: which  electricity  is  caused  to  react  on  the  iron  and  so 
heighten  its  magnetism;  and  this  increased  magnetism  in  its 
turn  gives  rise  to  more  powerful  electrical  effects,  and  so  on, 
until  a  limit  is  reached,  depending  partly  on  the  velocity  of 
the  motion,  partly  upon  the  relative  apportionments  of  the 
size  and  quality  of  the  wire  and  iron  employed  in  its  con- 
struction, and  partly  on  the  resistance  throughout  the  cir- 
cuit. ^Although  this  principle  was  fully  understood,  and  de- 
scribed by  Soren  Hjorth,  of  Copenhagen,  in  his  patents,  dated 
October,  1854,  and  April,  1855,  yet  the  name  "dynamo"  (from 
dynamisy  Gr.,  force]  does  not  appear  to  have  been  used  in 
this  connection  until  Dr.  Werner  Siemens  employed  it  in  a 
communication  to  the  Berlin  Academy,  January  17,  1867. 

§  2.  Faraday"1  s  Discovery. — The  closeness  of  the  relation- 
ship between  the  phenomena  which  we  call  electricity  and 
magnetism  had  struck  many  philosophers  of  the  eighteenth 
century.  Oersted,  of  Copenhagen,  in  1819,  was  the  first  to 
prove,  by  a  series  of  masterly  experiments,  the  magnetic 
properties  of  current  electricity;  Ampere  and  Arago,  in 
France,  and  Sir  Humphry  Davy  in  England,  then  distin- 
guished themselves  by  their  zeal  and  activity  in  this  research; 
but  the  keystone  of  the  arch  was  laid  when  Faraday,  in 
November,  1831,  showed  that  it  was  possible  to  call  forth 
electric  currents  by  means  of  a  magnet.  In  order  that  the 


479 

reader  should  have  an  intelligent  knowledge  of  the  principles 
which  underlie  the  construction  of  the  dynamo,  it  would  be 
well  for  him  to  repeat  some  of  the  experiments  about  to  be 
described,  more  especially  as  they  are  easy  of  performance 
and  trifling  in  cost. 

The  first  thing  required  will  be  a  galvanometer,  an 
instrument  for  indicating  the  presence  of  current  electricity 
(and  in  some  cases  to  measure  its  quantity).  To  make  this, 
a  piece  of  spring  steel,  2  inches  long  and  y&  of  an  inch  in 
width,  is  "softened"  by  heating  the  middle  portion  over  a 
gas  jet  or  other  flame,  until  red  hot,  then  allow  to  cool 
gradually.  By  laying  this  across  a  knife  blade  the  exact 
center  is  found  and  marked.  By  means  of  a  screw-arill  a 
hole  about -3\>  of  an  inch  diameter  clear  through  the  center 
of  this  steel  "needle,"  as  it  is 
called,  is  bored.  By  filing  from  the 
center  toward  the  side  the  needle 
is  brought  to  the  shapev  of  a 
lozenge,  as  seen  at  Fig.  i,  A. 
Holding  this  needle  by  means  of  a 
piece  of  copper  wire  passed 
through  the  hole,  it  is  heated  to 
dull  redness  over  a  flame  and 
plunged  into  cold  water  to  restore 
its  temper.  A  piece  of  brass  rod, 
y%  of  an  inch  in  diameter,  and 
about  y%  of  an  inch  long,  is  now 
soldered  centrally,  just  over  the 
hole.  This  is  easily  done  by 

cleaning  the  needle  with  a  bit  of  sandpaper,  specially 
round  the  hole,  cleaning  also  the  little  piece  of  brass 
rod,  on  its  end,  then  putting  a  little  piece  (as  big  as  a  grain 
of  mustard-seed)  of  plumbers'  solder  just  over  the  hole  bored 
in  the  needle.  Holding  the  needle  with  a  pair  of  forceps  (a 
little  rosin  powder  having  been  previously  applied  roundabout 
the  hole)  over  the  flame  of  a  spirit-lamp  or  gas-burner,  wil1 
cause  the  solder  to  melt  and  adhere  to  the  steel.  The  piece 
of  brass  is  now  taken  up  with  another  pair  of  forceps,  and 
laid  (flat  side  downward)  as  centrally  as  possible  over  the 
hole.  Keeping  the  needle  still  over  the  flame,  the  solder 
will  also  flow  round  the  brass  and  adhere  to  it,  making  a  firm 
junction,  when  it  may  be  removed  from  the  flame,  and  placed 
at  once  on  a  cold  metal  or  stone  surface.  It  should  now 


present  the  appearance  shown  at  Fig.  i,  B.  Any  solder 
which  may  have  exuded  from  between  the  brass  and  steal 
should  be  filed  away.  Using  the  same  bit  in  the  screw-drill 
that  was  employed  originally  to  bore  the  hole  through  the 
steel,  a  conical  hole,  reaching  nearly  but  not  quite  to  the 
opposite  surface  of  the  brass  piece,  is  drilled  from  the  hole  in 
the  steel.  This  serves  as  a  pivot  on  \vhich  to  poise  the  needle. 
A  trial  may  now  be  •  made  to  find  whether  the  needle 
is  fairly  centered;  but  no  attempt  need  be  made  yet  to  balance 
it  if  not  true.  Having  cut  off  the  head  of  a  fine-pointed  pin, 
drive  it,  blunt  end  downward,  into  the  center  of  a  little  slab 
of  well-seasoned  pine  3  inches  by  3  inches  by  }<  an  inch, 
leaving  not  less  than  %  of  an  inch  protruding.  On  the  point 
poise  the  needle,  and  mark  with  a  pencil  the  end  which 
hangs  (if  either  does).  Fig.  i,  C,  will  show  what  is  meant. 
The  needle  must  now  be  magnetized  by  being  allowed  to 
remain  for  some  tiiue  (twenty  minutes  or  half  an  hour)  across, 
and  in  contact  witL.  the  poles  of  a  horse-shoe  magnet,  care 
being  taken  that  having  once  placed  the  needle  in  one  position 
'  it  should  not  be  reversed,  as  its  polarity  would  be  reversed 
if  this  were  done;  and  since  in  our  latitude  the  north-seeking 
pvle  of  a  freely  suspended  needle  Jiangs  downward,  if  the  needle, 
when  tried  previous  to  magnetizing,  had  one  end  heavier  than 
the  other,  ///<?/ end  must  be  placed  against  the  north  pole  of  the 
horse-shoe  imgnet,  by  which  means  it  will  acquire  south-seek- 
ing polarity,  and  consequently  neutralize  to  a  certain  extent 
the  inclination  of  the  poised  needle.  After  magnetization 
it  should  be  again  poised,  any  deviation  from  the  horizontal 
line  noted  auxi  corrected  by  cautiously  filing  the  needle  on 
one  of  its  flat  sides,  at  its  heavier  extremity,  with  a  fine  file, 
until  perfect  equilibrium  is  obtained.  Fig.  i,  D,  illustrates 
the  position  in  which  the  needle  should  be  placed  with  rela- 
tion ta  the  magnet  during  magnetization.  When  the  needle 
has  betu  mrell  balanced  it  ought  to  turn  very  freely  on  its 
pivot,  making  several  free  swings,  but  finally  taking  up  a 
position  pointing  norfh  and  south.  It  should  also  show  de- 
cided polarity  when  tested  with  a  magnet;  that  is  to  say,  one 
extremity  should  be  strongly  attracted,  and  the  other  just  as 
stron  iy  repelled  on  the  approach  of  the  north  pole  of  a 
horso-shoe  or  bar  magnet.  When  all  these  conditions  have 
been  satisfied,  it  will  be  well  to  mark  with  a  pencil  the  letter 
N  on  the  extremity  of  the  needle,  which  is  repelled  by  the 
north -seeking  (or  marked)  end  of  the  magnet.  This  extrem- 


ity  will  be  the  north-seeking  end  of  the  needle,  and  is  gener- 
ally (though  inaccurately)  called  its  north  pole. 

$  3.  We  have  now  succeeded  in  making  and  poising  a 
magnetic  needle.  In  so  doing  we  have  learned  two  impor- 
tant facts:  (a)  that  steel  becomes  permanently  magnetic 
when  placed  in  proximity  to  a  magnet;  (b)  that  each  pole  of 
the  new  magnet  thus  formed  evinces  a  polarity  of  opposite 
kind  to  that  possessed  by  the  pole  of  the  original  magnet 
which  induced  its  magnetic  condition;  in  other  words,  the 
north  pole  of  the  original  magnet  induces  south  polarity  in 
that  portion  of  the  steel  nearest  to  it,  while  the  south  pole 
induces  north  polarity. 

Our  next  step  is  to  surround  the  needle  with  a  coil  of  in- 
sulated copper  wire.  To  this  end  a  piece  of  wood  2^  inches 
wide  by  i^  inches  thick,  and  of  convenient  length  to  hold  in 
the  hand,  is  prepared  as  a  form,  the  edges  being  slightly 
rounded  to  admit  of  the  wire  being 
slipped  off;  this  is  then  wound 
with  about  ten  feet  of  No.  30  silk- 
covered  copper  wire,  as  shown  at 
Fig.  2,  A,  leaving  about  three 
inches  of  wire  projecting  at  each 
extremity,  The  four  corners  of 
the  rectangle  thus  formed  should  be  bound  with  silk,  so  as  to 
prevent  uncoiling  when  the  rectangle  is  drawn  off  the  wooden 
form.  The  coil,  on  removal  from  the  form,  should  present 
the  appearance  shown  at  B,  in  which  the  ends  of  the  silk 
used  to  tie  the  corners  are  purposely  exaggerated  in  length, 
the  better  to  show  their  position.  The  center  of  the  coil 
being  found,  the  wires  forming  one  of  the 
flat  sides  are  slightly  parted  by  means  of 
a  blunt  pin  (care  being  taken  not  to  abrade 
the  silken  covering),  and  the  coil  passed 
over  the  pin-point  fastened  in  the  center 
of  the  little  baseboard  above  described 
(§  2),  and  attached  thereto  with  a  little 
dab  of  hot  sealing-wax,  or,  better  still,  with  good  elastic 
cement.  The  needle  is  then  replaced,  and  tried,  to  see 
whether  it  "oscillates  freely  without  catching  at  any  point  in 
the  coil.  The  two  free  ends  of  the  wire  are  now  to  be  de- 
nuded of  their  silk  covering,  cleaned  with  a  bit  of  sand  or 
flass  paper,  and  attached  to  two  small  binding  screws  (those 
nown  as  telephone  binding-screws,  and  sold  at  most  elec- 


482 

tricians'  at  50  merits  per  dozen, 
will  do  admirably),  inserted 
one  at  each  corner  of  the  base- 
board. The  galvanometer  or 
multiplier  is  now  complete, 
and  should  appear  as  figured  at 
C.  When  all  is  in  position, 
note  from  which  binding-screw  starts  the  wire  which  goes 
over  the  needle.  Mark  this  binding-screw  by  writing  rt  over  " 
near  it.  The  galvanometer  is  used  to  detect  the  presence  of 
current  electricity  by  causing  any  such  current  to  pass 
through  the  coils  of  the  instrument.  For  this  purpose  the 
two  opposite  extremities  of  any  circuit,  through  which  it  is 
supposed  a  current  is  flowing,  are  each  connected  to  one  of 
the  binding-screws.  If  a  current  passes,  the  needle  (which 
previously  must  be  made  to  lie  parallel  with  the  coil,  by 
turning  the  baseboard  round  until  the  coil  points  north  and 
south,  like  the  needle)  will  immediately  start  out  from  its 
position  of  parallelism  with  the  coil,  and  take  up  a  position 
which  will  approach  nearer  to  right  angles  with  the  coil,  in 
proportion  as  the  current  is  stronger.  To  test  whether  the 
galvanometer  just  made  be  fairly  delicate,  attach  a  piece  of 
copper  wire  about  ^  of  an  inch  thick  and  six  inches  long  to 
one  of  the  binding-screws;  to  the  other  attach  a  similar  piece 
of  iron  wire.  Now  bring  the  free  ends  of  the  wire  (by  bending) 
within  l/%  of  an  inch  of  each  other.  Turn  the  baseboard  round 
until  the  north  end  of  the  needle  points  between  the  two 
binding-screws,  perfectly  parallel  to  the  coil.  Put  a  single 
drop  of  vinegar  on  a  little  piece  of  glass,  and  bring  it  under 
the  two  ends  of  the  wires,  which  must  be  lowered  until 
they  are  both  in  the  drop  of  vinegar,  but  do  not  touch 
each  other.  By  the  action  of  the  vinegar  on  the  two 
metals,  an  electrical  disturbance  is  set  up,  which  produces  a 
so-called"  current "  which  starts  from  the  iron;  passes  through 
the  vinegar,  along  the  copper  wire,  through  the  coils  of  the 
galvanometer,  and  back  again  into  the  iron,  this  action  being 
continuous  as  long  as  the  vinegar  acts  on  the  iron.  Simulta- 
neously with  this,  the  needle  is  seen  to  deflect  from  the  line 
of  the  coil,  and  if  our  galvanometer  LG  a  success,  it  should 
stand  out  at  least  20°  from  the  centrai  line  of  the  coil.  Far- 
aday's great  discovery,  on  which  all  dynamos  are  based,  con- 
sisted in  proving  that  a  magnet  could  be  caused  to  excite  a 
current,  similar  to  that  produced  by  the  action  of  acids  on 


metals.  We  can  now  repeat  his  experiment 
with  the  aid  of  our  galvanometer.  Let  A, 
Fig.  3,  be  a  rod  of  %  inch  soft  iron,  about 
6  inches  long,  bent  to  the  shape  of  the  letter 
U,  and  wound  round  its  central  portion  with 
about  100  feet  of  No.  24  cotton-covered 
copper  wire,  the  two  ends  of  which  (about  a 
yard  each  end)  having  been  stripped  of  their 
covering,  must  be  attached  to  the  binding- 
screws  of  the  galvanometer.  If  a  good  horse- 
shoe magnet,  B,  be  placed  in  contact  with 
the  two  legs  of  the  coiled  U,  this  latter  being 
kept  motionless,  while  the  magnet  is  alter- 
nately approached  to  and  separated  from 
it,  it  will  be  found  that  the  needle  of  the 
galvanometer  is  powerfully  affected,  first  in 
one  sense  and  then  in  the  other,  according 
to  whether  we  make,  or  break  contact  with 
the  U,  or  armature ',  as  it  is  called.  We  shall 
also  find  that,  although  the  most  powerful 
effects  are  noticed  when  actual  contact  and 
actual  separation  take  place,  yet  currents  are 
also  produced  on  approaching  or  removing 
gnet  to  or  from  a  distance.  In  other  words,  motion 
field  of  a  magnet  gives  rise  to  electricity.  If  we  study 
the  effects  thus  obtained,  we  shall  find  that  they  differ  in 
some  points  very  markedly  from  those  obtained  by  the  action 
of  acids  on  metals  (voltaic  electricity — galvanism),  inasmuch 
as  first,  the  action  is  not  continuous  ;  secondly,  it  is  contrary 
in  direction  when  contact  is  made  to  what  it  is  when  it  is 
broken. 

§  4.  The  student  will  do  well  to  compare  the  effects  pro- 
duced on  the  galvanometer  by  the  battery  current,  and  by  the 
current  obtained  from  the  magnet.  Any  single  cell  will 
do  for  this  purpose ;  and  in  order  to  have  an  intelligent  per- 
ception of  what  takes  place,  the  student  must  bear  in  mind, 
that  in  the  battery  itself,  the  electricity  (undulatory  move- 
ment of  the  molecules)  passes  from  the  zinc  to  the  negative 
plate  (be  it  copper,  silver,  platinum,  or  graphite),  while  out- 
side  the  battery,  the  electricity  passes  from  this  latter  round 
through  the  wires,  galvonometer,  or  other  circuit  open  to  its 
passage,  back  again  to  the  zinc  plate.  (See  Fig.  4,  where  the 
direction  of  the  undulation,  or  "current, "is  shown  by  the 


arrows ;  the  plate  marked  Z  being  zinc,  the  one  marked  C 
being  carbon,  copper,  or  other  conductor ;  W  W  being  the 
wires  forming  the /<?/£$•  or  electrodes. )  If  the  positive  pole  (the 
one  from  which  the /'current  "  is  flowing,  the  wire  attached 
to  the  C  plate)  of  such  a  battery  be  connected  to  the  galva- 
nometer by  means  of  the  binding-screw  marked  "  over,"  the 
other  pole  being  attached  to  the  other  binding-screw,  the  north 
pole  of  the  needle  having  previously  been  adjusted  so  as  to  lie 
between  the  two  binding-screws,  it  will  be  found  that  the 
north  pole  of  the  needle  will  deflect  to  the  left  of  the 
line  of  the  coil ;  the  operator  being  sup- 
posed to  be  standing  at  the  binding-screw 
end  of  the  galvanometer.  Since  the  wire 
of  our  coil  returns  below  the  needle,  it 
is  evident  that  a  positive  current  (an  out- 
flow  of  undulation)  passing  over  the  north 
pole  of  a  horizontally  suspended  needle, 
of  a  negative  current  (an  influx  of  undula- 
tion) passing  under  such  a  north  pole, 
causes  it  to  deflect  to  the  left. 

If  we  disconnect  the  battery  and  reverse 
the  connections — that  is,  join  the  negative 
pole  (the  wire  coming  from  the  zinc)  to  the 
binding-screw  marked  "  over, "  the  other  pole 
being  connected  to  the  other  screw — the 
opposite  effect  results,  viz.,  the  north  pole 
now  deflects  to  the  right  of  the  coil.  This 
will  be  understood  by  reference  to  Fig.  5,  in 
which  a  represents  the  effect  of  the  positive 
current  flowing/>ww  the  operator  over  the 
needle,  the  north  pole  in  both  illustrations 
being  nearest  to  him ;  in  b  the  positive 
current  is  supposed  to  be  flowing  from  the  operator,  below 
the  needle,  in  either  case  returning  to  the  battery  the  oppos- 
ite way. 

§  5.  The  effect  will  enable  us  at  once  to  recognize,  by 
means  of  our  galvanometer,  the  direction  in  which  a  current 
is  traveling;  for,  on  connecting  the  two  terminals  of  any 
source  of  electricity  to  the  binding-screws  of  the  galvanom- 
eter, ..while  the  north  pole  is  in  a  line  with  the  coils,  be- 
tween the  two  binding-screws,  the  operator  facing  the  north 
pole  of  the  needle,  it  is  evident  that  if  the  north  pole 
of  the  needle  is  deflected  to  the  left,  the  terminal  at- 


485 

tached  to  the  binding-screw  marked  "  over  "  is  positive;  but 
that  if  the  north  pole  deflects  to  the  right,  then  the  said 
terminal  is  negative.  It  must  be  borne  in  mind  that  by  the 
term  positive  in  this  connection  is  meant  the  point  from 
which  electricity  is  flowing,  negative  being  the  point  toward 
which  it  is  flowing,  or  at  which  it  enters.  This  power  of 

NO.  C. 


r 

recognizing  the  direction  of  a  current  will  be  found  of  great 
service  to  us  in  the  construction  of  the  dynamo. 

§  6.  Returning  now  to  our  experiments  with  the  magnet 
(see  latter  portion  of  §  3),  and  using  in  preference  a  straight 
soft  iron  rod,  about  6  inches  in  length  and  J^  inch  in  diameter, 


coiled  with  about  loo  feet  of  No.  24  covered  wire  as  pur 
armature,  and  a  good  bar  magnet  to  produce  the  electrical 
effects,  we  shall  find,  on  coupling  up  the  armature  wires  to 
the  galvanometer,  and  approaching  one  end  of  the  armature 
to  or  receding  it  from  the  north  pole  of  the  magnet,  that  the 
-electrical  flow  set  up  is  always  in  one  direction  in  approach- 
ing or  making  contact,  and  in  the  opposite  direction  on  re- 
ceding or  breaking  contact.  Fig.  6  will  make  this  clear. 
The  arrow  at  a  shows  the  direction  of  the  current  produced 
on  approaching  or  making  contact  with  the  north  pole  of  a 
magnet;  b  illustrates  the  direction  of  current  produced  on 
receding  from  or  breaking  contact  with  the  north  pole  of  a 
magnet.  If  now  we  reverse  the  experiment  by  presenting  the 
south  pole  of  the  magnet  to  the  coiled  armature,  we 
shall  find  that  the  direction  of  flow  is  also  reversed;  that  is 
to  say,  the  withdrawal  of  a  south  pole  produces  the  same 
effect  as  the  approach  of  a  north  pole,  and  vice  versa,  the 
approach  of  a  south  pole  is  equivalent  in  its  effects  to  the 
recession  of  a  north  pole.  It  must  be  noted  that  the  direction 
in  which  the  wire  is  coiled  round  the  soft  iron  rod  (or  arma- 
ture), while  it  has  no  influence  on  the  direction  of  the  elec- 
trical ctorrent  set  up  round  the  iron  rod  (which  is  always  the 
reverse  to  the  hands  of  a  clock  in  the  face  approaching  the 
north  pole)  determines  the  extremity  of  the  said  wire  at 
which  the  current  leaves  or  enters  the  coil.  In  the  figure 
we  have  supposed  the  wire  to  be  wound  from  left  OVER 
toward  right ;  had  we  wound  our  rod  from  left  UNDER 
toward  right,  the  opposite  ends  of  the  wire  would  have  been 
respectively  +  and  — .  This  must  be  borne  in  mind  when  we 
proceed  to  actual  work. 

§  7.  Currents  can  produce  Magnetism, — If  we  take  the 
coiled  soft  iron  U,  of  which  we  made  use  §  3,  and  apply  it  to 
pieces  of  soft  iron,  nails,  filings,  etc.,  we  shall  find  that  it 
possesses  little  or  no  magnetic  power  of  attraction ;  but  if 
we  couple  the  projecting  ends  of  the  coiled  wires  one  to  each 
terminal  of  a  single-cell  battery,  we  shall  find  that  the  U  will 
become  powerfully  magnetic,  retaining  its  magnetism  as  long 
as  electricity  flows  around  the  coils,  but  losing  nearly  all  the 
instant  that  the  flow  is  caused  to  cease,  either  by  breaking 
connection  with  the  battery  or  by  any  other  interruption. 
The  rapidity  and  completeness  with  which  the  iron  loses  its 
magnetism  depends  almost  entirely  on  its  softness  and  purity. 
Anything  which  tends  to  put  a  strain  on  the  molecules  of  the 


iron,  such  as  hammering,  filing,  twisting,  sudden  cooling, 
vibration,  etc.,  render  it  liable  to  retain  magnetism,  or 
increase  its  coercitive  force  ;  whereas  raising  to  a  high  tem- 
perature and  very  gradual  cooling,  which  allows  the  mole- 
cules to  range  themselves  with  little  or  no  strain,  furnishes  a 
soft  iron,  eminently  incapable  of  retaining  magnetism,  or 
possessing  little  coercitive  force. 

$  8.  The  direction,  in  which  the  flow  of  electricity 
takes  place  around  the  iron  bar  decides  which  end  of  the 
bar  acquires  north-seeking,  and  which  south-seeking  po- 
larity. Let  us  suppose  as  in  Fig.  7>  A,  that  one  ex- 
tremity of  the  bar  be  made  to  face  us,  and  that  the 
current  be  caused  to  flow  in  the  direction  of  the  motion 
of  the  hands  of  the  clock;  in  this  case,  the  farther  ex- 
tremity of  the  bar  becomes  a  north-seeking  pole,  while  the 
nearer  extremity  becomes  south-seek- 
ing. The  direction  of  the  current, 
and  consequently  the  polarity  of  the 
bar,  may  be  reversed  by  joining  up 
the  opposite  electrodes  cf  the  battery 
(or  other  source  of  electricity)  to  the 
ends  of  the  wire  coiled  round  the  bar, 
as  shown  at  B;  where,  as  the  wire  is 
joined  to  the  electrodes  in  a  manner 
just  the  reverse  to  that  shown  at  A, 
so  also  the  current  enters  at  the  op- 
posite end  of  the  wire,  and  produces 
I\J»  contrary  magnetic  effects.  The  same 
i  result  may  also  be  attained  by  coiling 
I  the  wire  around  the  bar  in  the  con- 
trary direction,  while  leaving  the 
connection  with  the  electrodes  un- 
changed, as  represented  at  C  (Fig.  70).  Perhaps  the  simplest 
means  of  remembering  the  relation 
which  exists  between  the  direction  of  /«?  r* 

the  current  and  the  position  of  the 
magnetic  poles  produced,  is  one  known 
as  "  Ampere's  Rule,"  in  which  the  ex- 
perimenter considers  himself  to  be 
swimming  head  foremost,  •with  the 
current,  along  the  wire,  always  facing 
the  iron  core;  then  the  NORTH-SEEK- 
ING POLE  will  always  be  at  his  LEFT  HAND.  (See  Fig.  8). 


§  9-  It  must  be  borne  in  mind,  as 
being  of  the  greatest  importance  in 
the  construction  of  successful  dyna- 
mos, that  although  steel,  or  hard 
iron,  when  subjected  to  this  induc- 
ing action  of  the  current,  becomes 
magnetic,  yet  it  does  not  acquire 
nearly  such  powerful  magnetism  as 
soft  iron;  and,  in  fact,  the  softness 
of  the  iron,  and  its  capacity  for  be- 
coming powerfully  magnetic,  run  side  by  side.  On  the  other 
hand,  it  must  not  be  forgotten,  as  we  learned  at  §  7,  that  the 
softer  the  iron  the  sooner  it  loses  the  magnetism  imparted  to 
it;  while  the  harder  brands  of  iron  (and  more  especially  steel) 
retain  nearly  all  the  magnetism  which  it  is  possible  to  confer 
upon  them. 

§  10.  The  student  who  has  carefully  and  intelligently 
performed  the  experiments  described  in  the  previous  sec- 
tions, will  now  find  himself  in  a  position  to  understand  the 
principles  which  underlie  the  construction  of  the  dynamo, 
even  though  he  may  have  little  or  no  previous  knowledge  of 
electricity.  ^The  first  machine  constructed  after  Faraday's 
discovery  was  that  of  H.  Pixii,  in  1832.  In  this  machine 
a  powerful  horse-shoe  magnet  was  caused  to  rotate  rapidly 
before  a  soft  iron  U-piece,  wound  with  insulated  cop- 
per wire,  the  two  extremities  of  which  were  prolonged  by  two 
brass  springs  pressing  against  a  rotating  split  collar  of  brass, 
whose  office  was  to  rectify  the  direction  of  the  currents  pro- 
duced by  rotation  of  the  magnet,  before  the  iron  core;  cur- 
rents which,  as  we  have  set.  (^  4),  are  in  different  directions, 
according  to  \vhether  a  given  pole  of  a  magnet  is  approaching 
to  or  receding  from  the  core.  This  arrangement  for  causing 
alternating  currents  to  flow  in  one  direction,  is  known  as 
the  commutator,  and  it,  or  some  modification  of  it,  is  most 
extensively  used  in  all  dynamos  in  which  it  is  of  importance 
that  the  current  should  flow  in  one  direction  only.  The 
chief  disadvantage  in  this  machine  was  that  of  having  to 
rotate  a  heavy  magnet  (built  up  of  a  number  of  thin  steel 
plates),  since  the  mere  rotation  tended  to  destroy,  or  at  all 
events,  to  weaken  its  magnetism.  In  1833  Mr.  Sexton  had 
the  happy  idea  of  fixing  the  heavier  and  causing  the  lighter 
portions  of  the  apparatus  to  rotate:  in  other  words,  the 
magnet  (or  magnets)  was  now  made  a  fixture,  while  the  U- 


shaped  soft  iron  armature,  with  its  surrounding  coils  of  wire, 
was  caused  to  rotate  rapidly  before  it,  on  axis  or  spindle, 
either  by  gear-wheels  or  wheel  and  band.  Mr.  E.  M.  Clarke, 
in  1834,  noticed  that  the  thickness  of  the  wire  coiled  round 
the  armature  had  a  considerable  influence  on  the  nature  of 
the  current  produced  by  these  machines.  If  the  wire  em- 
ployed be  very  thin,  say  about  the  TJC  of  an  inch  in  diameter, 
and  a  large  number  of  convolutions  be  coiled  around  the 
legs  of  the  armature,  the  electricity  produced  is  of  high 
tension,  capable  of  overcoming  considerable  resistances,  and 
of  giving  severe  shocks.  If,  on  the  contrary,  a  smaller 
quantity  of  a  much  thicker  wire,  say  from  the  ^  to  the  ^ 
of  an  inch  be  made  use  of,  the  current  produced  is  that 
Renown  as  a  quantity  current,  o^  a  "  large  "  current,  p<  s^ess- 
ing  but  little  power  of  overcoming  resistances,  not  capable 
of  giving  shocks,  but  giving  fine  large  sparks,  and  able  to  de- 
compose water,  and  other  chemical  bodies.  ^Clarke  usually 
furnished  two  armatures  with  his  machines,  one  wound  with 
about  1, 500  yards  of  covered  wire  /g  of  an  inch  in  diameter, 
which  he  designated  the  "  intensity  "  armature;  the  other, 
wound  with  about  40  yards  of  wire  Tl8-of  an  inch  thick,  to  which 
he  gave  the  name  of  the  "  quantity  "  armature.  One  pecu- 
liarity of  the  machines  turned  out  by  Clarke  was  the  fact  o£ 
the  rotating  U-shaped  armature  being  made  to  rotate  near 
the  flat  sides  of  the  magnet  instead  of  in  front  of  the  poles. 
This,  though  it  facilitates  somewhat  the  mechanical  arrange- 
ments, is  open  to  some  objections 
on  the  score  of  lesser  efficiency,  since 
the  most  active  portion  of  the  mag- 
net is  certainly  in  front  of  the  poles. 
As  Clarke's  machine  embodies  near- 
ly all  the  principles  found  in  later 
dynamos,  we  shall  give  an  illustra- 
tion, together  with  detailed  explana- 
tion of  the  commutator,  etc.,  in  our 
next  paragraph. 

§  Ii.^  In  Clarke's  machine  the 
horseshoe  magnet,  A,  Fig.  9,  is 
clamped  to  a  rigid  backboard,  which 
is  mortised  to  the  baseboard.  In 
front  of  this  magnet,  and  in  close  proximity  to  its  poles,  is  the 
armature  B  B',  which  can  be  made  to  rotate  on  its  axis  at 
<?9  which  passes  right  through  the  backboard,  behind  which 


49° 

k  is  supported  on  bearings.     The  distant  end  of  the  axis  is 

fitted  with  a  pulley,  around  which  plays  a  band  or  gut  coming 

from    the  fly-wheel  /     On   turning  the  handle  of  /,    the 

small    pulley    enters    into    rotation,    carrying  with    it   the 

armature.     This   armature   (which    represents   the   U  -piece 

described   at   $  3,   Fig.   3)   is    really  constructed    of  three 

pieces  of  very  soft  iron,  two  short 

circular  bars  and  a  cross-piece,  held 

together  by  screws,  as  shown  at  b. 

Around  the  two  bars  is  carefully 

coiled  the    insulated*  copper  wire, 

in  such  a  manner  that,  if  the  bars 

were  straightened  out,  the  winding 

would  be  always  in  one  continuous  di- 

rection,either  from  left  over  to  right  ^ 

or  vice  versd,  and  the  two  extreme 

ends  of  the  wire  are   brought  out 

and  joined  metallically  with  the  two 

metal  half-cylinders  which  form  the 

commutator  c.     This  commutator 

is  illustrated  more  fully  at  Fig.  10 


i  Against  the  commutator  press  the  two  brass  springs  < 
</',  to  which  are  connected  the  wires  e  and  <?',  which  form  the 
real  electrodes  or  poles  of  the  machine.  Fig.  lo  shows  how 
the  wire  is  wound  round  the  two  soft  iron  cores  B  and  B',  which 
are  screwed  to  the  soft  iron  cross-piece  at  A  and  A',  thus  con- 
stituting virtually  a  coiled  U-piece.  The  two  ends  of  the 
wire  which  forms  these  bobbins  come  out  at  opposite  sides  of 
the  bobbins,  and  are  soldered  or  screwed  to  the  naif  -cylinders 
(of  brass)  c  and  c',  as  shown  at  b  and  b  '.  In  order  that  the 
two  cheeks  of  the  commutator,  c  and  c'  (which  are  shown  sep- 
arately to  the  right-hand  of  Fig.  10),  should  not  allow  the 
electricity  to  escape  from  one  to  the  other,  the  spindle  which 
carries  the  bobbins  B  B'  and  the  cross-piece  A  A',  is  encased 
in  a  thick  ring  of  ivory,  baked  boxwood  or  other  insulator, 
which  in  the  illustration  is  shaded  darkly. 

FUNCTION  OF  THE  COMMUTATOR.  —  §  12.  If  we  follow 
one  of  the  bobbins  of  the  armature  during  its  revolution  be- 
fore the  poles  of  the  magnet,  we  shall  find  that  it  change?,  its 
magnetic  condition,  and  consequently  its  electrical  state,  twice 
during  each  revolution.  Let  us  take,  for  instance,  the  bob- 

*  A  body  is  said  to  be  insulated  when  surrounded  by  substances 
which  pretent  the  passage  of  electricity. 


491 

bin  B'  in  either  figure  in  its  rotation  from  the  north  pole  ©f 
the  magnet  toward  the  south  pole,  as  we  learnt  at  §  6,  leav- 
ing a  north  pole  or  approaching  a  south  pole  produces  the 
same  effect;  and  this  effect  will  be  that  a  current  will  flow 
round  the  bobbin  from  the  right  over  toward  the  left.  Hence, 
if  the  wire  (which  is  coiled  round  the  bobbin  in  the  same  di- 
rection) have  its  corresponding  extremity  joined  to  any  cir- 
cuit, this  extremity  will  be  found  to  be  negative.  In  practice 
this  extremity  is  actually  connected  with  the  cheek  ff  of  the 
commutator.  This  cheek  c1  during  the  whole  of  the  semi- 
revolution  of  the  bobbin  B'  from  north  to  south,  is  being 
pressed  against  by  the  spring  d1,  which,  with  its  wire  e'9  is 
consequently  kept  continuously  in  a  negative  state  until  the 
bobbin  B'  has  arrived  quite  opposite  the  south  pole  of  the 
magnet.  At  this  instant  the  spring  d'  touches  neither  of  the 
brass  half-cylinders,  but  presses  against  the  ivory,  boxwood, 
or  other  insulator,  which  separates  the  two  half-cylinders  of 
the  commutator  c  and  c' .  Hence,  no  current  flows;  but  di- 
rectly Cleaves  the  middle  of  the  south  pole  and  begins  to 
complete  the  under  half  of  the  revolution,  its  cheek  comes 
into  contact  with  the  spring  on  the  opposite  side,  d.  f|But 
now  we  find  that  the  bobbin  B'  is  leaving  a  south  pole  to  ap- 
proach a  north  pole;  therefore,  according  to  §  6,  the  current 
is  flowing  in  the  opposite  direction  round  the  bobbin.  There- 
fore the  spring  d  collects  from  the  cheek  c' positive  electricity. 
What  has  been  said  of  bobbin  B7  is,  of  course,  equally  true  of 
bobbin  B  at  similar  points  of  its  revolution;  hence  we  see  that, 
although  each  bobbin  becomes  alternately  north  and  south  as 
it  approaches  the  south  or  north  pole  of  the  permanent  magnet, 
and  sends  therefore  a  current  alternately  in  contrary  direc- 
tions, yet,  since  (owing  to  the  insulated  half -cylinders)  we 
are  able  to  cause  one  spring  to  pick  up  the  current  from  the 
bobbins  whilst  the  free  extremity  of  their  encircling  wire  is 
sending  a  positive  current  only  (the  other  spring  picking  up 
the  current  only  whilst  the  free  extremity  of  the  coiled  wire 
is  negative),  it  follows  that  the  springs  d  and  d'  are  main- 
tained in  oppositely  electrified  conditions.  It  must  be  borne 
in  mind  that  the  wire  is  coiled  continuously  round  both  bob- 
bins; hence,  that  as  the  bobbins  are  always  exposed  at  the 
same  time  to  opposite  magnetic  influences,  so  the  conditions 
of  the  two  extremities  of  the  coiled  wires  are  electrically 
opposite — viz.,  while  one  is  positive  the  other  is  negative^ 
and  vice  versd;  but  that  as  the  bobbin,  whichever  it  be, 


492 

which  travels  from  north  over  to  south  has  the  free  extremity 
of  its  wire  always  negative  and  in  connection  with  the  spring 
d'y  while  the  bobbin  (each  in  turn)  which  passes  under 
from  south  to  north  has  its  extremity  always  positive  and  in 
connection  with  the  spring  d!  it  follows  that,  providing 
always  the  motion  be  that  indicated  by  the  arrow  in  Fig.  10, 
the  spring  d1  will  always  be  kept  in  a  negative  condition, 
while  the  spring  d  will  simultaneously  be  positive. 

Since  the  comprehension  of  the  function  of  the  commuta- 
tor is  of  the  highest  importance  in  the  manufacture  of  the 
dynamo,  we  recommend  the  amateur  to  digest  carefully  the 
contents  of  this  last  section. 

§13.  The  next  great  step  in  the  development  of  the 
dynamo  was  the  application  of  the  current  generated  by  the 
armature  to  the  heightening  of  the  magnetism  of  the  magnets 
which  set  up  that  current  in  the  armature.  We  have  seen 
(§  7)  that  a  current  sent  round  a  mass  of  soft  iron  converts 
that  iron  into  a  magnet;  and  we  find  that  the  intensity  of 
magnetization  is,  up  to  the  point  of  saturation,  proportionate 
to  the  quantity  of  electricity  flowing  round  the  iron.  We 
also  know  that  magnets  produced  by  such  means  (that  is,  the 
passage  of  currents  around  soft  iron  cores)  are  much  more 
powerful  than  permanent  steel  magnets  of  equal  size  and 
weight^  Hence,  apart  from  the  question  of  less  expense  and 
greatei  constancy  (for  steel  magnets  gradually  lose  their 
power  by  the  continuous  motion  of  the  armatures  before 
their  poles),  there  is  actually  a  great  gain  in  efficiency  in  em- 
ploying electro-magnets  instead  of  permanent  magnets 
wherewith  to  induce  the  current,  in  Hjorth's  machine 
(which  was  perfected  so  far  back  as  October,  1854) 
two  compound  cast-iron  magnets  A  A  (Fig.  II),  which 
may  or  may  not  be  surrounded  by  a  coil  of  wire,  are 
bolted  to  the  frame  of  the  machine.  These  magnets 
are  shaped  like  the  letter  C;  and  in  the  gap  between 
the  poles  rotates  a  wheel,  B  B,  on  the  circumference  of 
which  are  fastened  several  armatures  consisting  of  soft  iron 
cores  wound  with  insulated  copper  wire,  the  ends  of  which 
are  brought  out  to  a  peculiarly  constructed  commutator, 
which  rectifies  the  dissimilar  currents  produced.  The  wheel 
(and  consequently  the  armatures)  is  caused  to  rotate  by 
means  of  the  rigger  C  and  driving-axle.  Around  these 
movable  armatures,  and  also  bolted  to  the  frame,  are  several 
soft  iron  cores  wound  with  insulated  copper  wire,  D  D  D  D. 


493 

The  currents  produced  in  the  first  instance  by  the  passage  of 
)he  armatures  before  the  poles  of  che  magnets,  A,  after  being 
tendered  uni-direction  by  means  of  a  commutator,  are  led  on 
trough  wires  to  the  coils  which  surround  the  soft  iron 
lores,  D  D  D  D.  These  become,  therefore,  powerful 
electro-magnets,  and  induce  in  their  turn  more  powerful  cur- 
rents in  the  armatures.  The  larger  currents  thus  produced, 
again  reacting  in  their  passage  on  the  electro-magnets,  super- 
*nduce  a  higher  state  of  magnetism  in  them,  and  this  again 
exalts  the  electricity  generated  in  the  armatures,  and  so  on 
until  the  limit  of  saturation  is  reached.  The  current,  after 
traversing  the  coils,  is  led  to  terminals  to  which  connection 
can  be  made  for  exterior  work. 

It  is  remarkable  that,  although  this  discovery  was  so 
important,  and  the  description  and  designs  were  so  clear  in 
the  specification,  so  little  attention  should  have  been  attracted 
to  it.  Soren  Hjorth  was,  indeed,  much  before  his  time, 
many  of  the  machines  now  doing  excellent  work  being 
simply  trifling  modifications  of  his  "  magneto-electric  bat- 
tery." 

§  14.'  The  intensity  of  electric  and  magnetic  effects  does 
not  increase  in  the  simple  proportion  of  the  nearness  of  the 
bodies  acted  on,  but  in  a  much  greater  ratio,  which,  in  the 
case  of  electrified  bodies  and  permanent  magnets,  is  directly 
as  the  square  of  the  nearness,  or  (what  amounts  to  the  same 
thing)  '^inversely  as  the  square  of  the  distance.  For  instance, 
we  find  that  a  magnet  which  exerts  a  "  pull  "  of  i  Ib.  on  a 
given  piece  of  iron  at  6  inches,  if  placed  at  3  inches,  or  twice 
the  nearness, "pulls  with  a  force  of  2  X  2  =  4lb.;  and  if  placed 
four  times  as  near,  namely  i^  inches,  pulls  with  a  force  of 
4  X  4  =  16  Ib. 

It  would  appear  that  in  the  case 
of  electro  magnets  the  ratio  between 
the  distance  and  the  effect  increases 
even  more  rapidly,  being,  according 
to  the  best  authorities,  equal  to  in- 
versely the  cube  of  th<>  distance  nearly. 
Hence  it  struck  Dr.  Werner  Siemens, 
of  Berlin,  that  if  the  armature  could 
be  constructed  of  such  a  form  as  to 
allow  of  its  remaining  always  very 
close  to  the  poles  of  the  magndt 
during  its  rotation,  greatly  exalted  electrical  effects  would 


494 


result;  and  in  1856  he  patented  in  this  country  the  specis 
form  of  armature  represented  at  Fig.  1 1  a,  so  well  known  as 
the  "Siemens"  or  "H -girder"  armature.  On  reference 
to  the  armatures  depicted  at  Figs.  9  and  10,  it  will  be  seen 
that  during  a  considerable  portion  of  their  rotation  they  are 
at  some  distance  from  the  legs  of  the  magnets,  and  even 
when  near  them  are  not  at  the  points  of  greatest  action. 

On  the  contrary,  the  Siemens  armature  is  placed  as 
nearly  as  possible  at  the  most  active  portion  of  the 
magnet's  poles — viz.,  their  extremities,  and  at  every  por- 
tion of  its  rotation  some  portion  of  the  armature  is  ex- 
posed  to  the  action  of  the  said  poles.  The  Siemens  arma- 
ture, as  shown  at  Fig.  u  a,  consists  of  a  cylinder  of  soft  iron 
between  three  and  four  times  as  long  as  its  diameter,  around 
the  sides  and  ends  of  which  is  cut  a  deep  groove  or  channel, 
rather  more  than  one-third  the  diameter  of  the  cylinder. 
This  is  shown  in  section  at  b.  The  soft  iron  cylinder  c,  has 
"brass  heads  and  axes  fitted  to  it  as  shown  at  f  and  g — the 
latter  carrying  a  pulley  or  rigger,  by  which  the  armature  can 
be  rotated;  while  the  former  is  encircled  by  the  commutator 
e  <?,  to  which  are  attached  the  two  ends  of  the  insulated  wire, 
which  is  wound  in  the  channel.  When  in  action  this  arma- 
ture is  placed  between  the  poles  of  a 
compound  horse-shoe  magnet,  and 
supported  on  trunnions  or  bearings  at 
both  ends;  two  springs  pressing  against 
the  commutator  carry  off  the  electric- 
ity generated  by  the  rotation  of  the 
armature,  the  motion  being  imparted 
by  means  of  a  band  passing  over  the 
pulley  at  the  farther  end  of  the  armature.  A  general  idea  oH 
this  arrangement  may  be  gathered  by  inspecting  Fig.  1 1  H. 

CURRENTS  GIVEN  BY  THESE  MACHINES  NOT  CONTINUOUS. 

$  15.  Since  the  direction  of  the  current  changes  at  every 
semi-revolution  of  the  armature  in  such  machines  as  those  of 
Clarke,  Pixii,  and  Siemens,  and  at  every  passage  of  the  com- 
pound armature  before  the  poles  of  the  inducing  magnets  in 
Soren  Hjorth's  machine,  we  are  constrained  to  use  a  com- 
mutator whenever  we  desire  to  produce  a  current  in  one  di- 
rection only.  But  the  commutator,  by  the  very  fact  of  its 
being  necessarily  constructed  of  two  or  more  portions  of  a 
metallic  cylinder,  separated  by  intervals  of  insulating  ma- 


dai 

Ifi 


495 

terial,  interrupts  the  passage  of  the  electricity  every  time  that 
the  springs  press  against  the  insulating  spaces.  Hence  the 
electricity  furnished  by  these  machines  partakes  more  of  the 
nature  of  rapidly  succeeding  waves,  than  of  a  steady  continu- 
ous current,  like  that  furnished  by  the  battery.  Still,  when 
the  armature  is  rotated  at  a  high  speed  (and  the  Siemens  re- 
quires to  be  driven  at  about  3,000  revolutions  per  minute,  to 
give  the  best  effects),  these  waves  succeed  each  other  with 
such  rapidity  as  to  simulate  a  steady  current,  no  break  in 
continuity  being  perceptible  to  ordinary  tests. 

RAPID  MAGNETIZATION  AND  DEMAGNETIZATION  PRODUCES 
HEAT, 

$  16.  It  is  found  that  the  sudden  change  from  north  magnet- 
ism to  south  magnetism,  which  takes  place  in  each  half  of  the 
above  described  armatures,  as  they  pass  over  from  before  a 
south  pole  to  before  a  north  pole  of  the  Inducing  magnets,  is 
accompanied  by  a  very  considerable  rise  in  temperature;  and 
that  this  rise  increases  with  the  rapidity  of  change  of  magnetism, 
which  in  its  turn  depends  on  the  rapidity  of  rotation.^  So 
marked  is  this  rise  of  temperature,  that  a  dynamo  fitted  with 
a  Siemens  armature  of  the  pattern  figured  at  §  14,  and  started 
at  an  initial  temperature  of  10°  C.,  rises  in  about  twenty  min- 
utes to  nearly  50°  C.,  when  driven  at  3,000  revolutions  per 
minute.  .  This  rise  in  temperature  is  detrimental  to  the  effi- 
ciency of  the  machine: — ist.  Because  the  wires  of  the  arma- 
ture, becoming  heated,  conduct  less  freely;  hence  loss  of 
current.  2d.  Because  the  armature  itself  is  not  capable  of 
such  intense  magnetisation  when  hot  as  when  cold  (a  red-hot 
mass  of  iron  is  hardly  affected  by  the  magnet);  hence  another 
loss  of  current.  3d.  Because  the  insulating  covering  of  the 
wire  is  impaired,  if  not  actually  ruined,  if  the  temperature 
exceeds  a  very  moderate  limit. 

For  these  reasons  it  is  important  to  keep  the  temperature 
of  the  armature  as  low  as  possible.  The  first  successful  step 
in  this  direction  was  taken  by  Dr.  Pacinotti,  of  Florence,  in 
1860,  who  constructed  an  armature  of  soft  iron,  in  the  shape 
of  a  ring  around  which  were  coiled,  in  successive  sections, 
helices  of  insulated  copper  wire,  the  ends  of  which  were 
joined  up  to  a  divided  ring  commutator  The  ring  armature 
of  soft  iron,  with  its  covering  of  wire,  was  supported  on  a 
central  axle,  and  rotated  before  the  poles  of  a  magnet,  either 
permanent  or  electro,  At  no  part  of  the  revolution  is  such 


496 

a  ring  taken  as  a  whole  farther  from,  or  nearer  to,  the  poles 
of  the  magnet;  and  although  its  magnetism  is  constantly 
changing,  yet^the  change  is  not  abrupt,  but  gradual  and  con- 
tinuous; as  will  be  explained  in  the  following  paragraph. 

PACINOTTI'S  RING  ARMATURE. 

§  17.  The  description  and  illustration  of  this  machine  is  t_ 
be  found  in  the  Nuovo  Cimento  for  the  year  1864,  under  the 
heading  of  "  Una  Descrizione  d'una  Piccola  Macchina  Elettro- 
Magnetica."  The  machine  itself,  as  described,  can  be  used 
either  as  a  motor,  or  as  a  generator  of  electricity;  and  its 
adaptability  to  either  purpose  was  specially  dwelt  upon  by 
Dr.  A.  Pacinotti,  in  his  communication;  but  it  is  only  under 
the  aspect  of  a  generator  that  we  shall  stop  to  consider  it 
here. 

Two  electro-magnets,  S,  N,  Fig.  12  (which  may,  or  may 
not,  be  united  together  below), 
are  fastened  to  a  baseboard,  and 
so  arranged  that  the  upper  ex- 
Uemity  of  one  is  a  north  pole, 
while  the  other  is  a  south  pole. 
These  poles  are  furnished  with 
semi-circular  prolongations  B  B, 
B'  B',  between  which  is  poised, 
on  the  axis  C  D,  a  soft  iron  ring 
A  A.  j?This  ring  is  attached  to 
the  axis  by  means  of  radial  arms. 
Coils  of  insulated  wire  are 
wrapped  round  the  ring  at  short 
intervals  about  its  periphery,  the 


IT*  9/2. 


end  of  each  coil  being  brought  down  the  axis  at  D  and  at- 
tached to  one  of  the  small  copper  strips  at  E  (of  which  there 
are  as  many  as  there  are  coils  around  the  ring),  the  wire 
beginning  the  next  coil  being  also  metallically  connected  to 
this  same  strip.  The  wire  terminating  the  next  coil  is 
fastened  to  the  next  strip,  from  whence  starts  a  fresh  coil, 
and  so  on,  until  all  the  strips,  which  form  the  compound 
commutator  E  are  connected  to  the  coils  in  such  a  manner 
'that  the  end  of  one  coil,  by  its  attachment  to  its  strip,  forms 
.the  commencement  of  the  next.  Consequently,  the  wire 
forming  the  coils,  although  capable  of  communicating  electri- 
cally with  the  springs  F  F  at  opposite  points  of  the  diameter 
of  the  cojrw^itator,  is  really  continuous.  The  ring  A  A  is 


497 

caused  to  rotate  by  means  of  the   rigger  G  and  the  driving 
belt  H. 

It  will  be  evident  on  reflection  that  the  half  of  ring  oppo- 
site the  pole  marked  N  will  acquire  by  induction  south 
magnetism,  while  the  half  facing  the  pole  S  will  for  a  similar 
reason  become  north.  Hence  the  ring,  whether  in  motion 
or  at  rest,  will,  provided  the  electro-magnets  be  active,  become 
a  circular  magnet,  with  the  south  pole  facing  the  north  pole 
or  the  electro-magnet,  and  its  north  pole  facing  the  south 
pole  of  the  electro.  When  the  ring  is  rotated,  though  if 
viewed  as  a  whole,  this  magnetic  condition  remains  unaltered, 
yet,  of  course,  any  given  portion  of  ,the  ring  will  gradually 
change  as  it  passes  over  from  one  "  horn  "  or  prolongation  of 
the  magnets  to  the  other).  Still,  the  change  which  takes 
place  is  not  abrupt,  but  gradual,  and  partakes  more  of  the 
nature  of  a  wave  than  of  shock.  So  also,  since  the  springs  of 
the  commutator  press  on  several  strips  at  the  same  time,  at  no 
time  is  contact  ever  entirely  broken  between  the  commutator 
and  the  springs;  therefore  the  current  which  is  produced  as  a 
continuous  wave,  always  in  one  direction,  is  collected  in  a  sim- 
ilar continuous  manner  by  the  springs  F  F,  and  may  be  em- 
ployed where  required  by  coupling  up  the  wires  I  I. 

This  machine,  discovered  more  than  twenty  years  ago,  em- 
bodies all  the  essential  characteristics  of  the  best  modern 
machines,  and  the  much  vaunted  machines  of  Gramme,  Brush, 
Siemens- Alteneck,  Maxim,  Edison,  etc.,  are,  at  best,  but 
trifling  modifications  of  the  Pacinotti  ring  machine — modifica- 
tions which  have  not  always  been  improvements.  Having 
now  brought  our  brief  sketch  of  the  essentials  of  a  dynamo 
to  a  close,  we  shall  proceed  in  our  next  section  to  construct- 
ive details. 

THE  PATTERNS. 

§  18.  In  the  dynamo  we  are  about  to  construct,  three  sepa- 
rate pieces  for  patterns  are  absolutely  necessary — viz.,  one  for 
the  armature,  one  for  the  legs  of  the  field  magnets,  and  one 
for  the  standard  which  supports  the  fly-wheel.  There  is  no 
necessity  for  the  amateur  to  put  himself  to  the  trouble  of  cut- 
ting out  a  pattern  for  the  flywheel,  since  such  wheels  with 
handles  already  fixed  can  be  had  for  a  dollar  or  so.  In  con- 
structing the  wooden  patterns,  from  which  the  iron  castings 
are  afterward  to  be  procured,  the  amateur  should  remember 
to  choose  dry,  well  seasoned  wood,  free  from  knots.  Red 
pine,  for  such  small  work  as  is  required,  will  be  found  as 


498 

good  as  «4ny.  Any  joints  that  are  absolutely  necessary  (and 
joints  should  be  avoided  as  much  as  possible)  should  be  at- 
tached together  with  dowels  and  glue.  It  must  be  borne  in 
mind  tha  the  molder  places  the  patterns  in  green  (moist)  sand, 
and  that  xhis  moisture  causes  ordinary  glued  joints  to  come  un- 
done or  e?\  /and.  Any  roughnesses  left  on  the  pattern  also  swell 
up,  catch  t\e  sand,  and  thus  destroy  the  sharpness  and  beauty 
of  the  mo\  \  and  therefore  of  the  resulting  casting.  It  is 
therefore  advisable,  after  having  got  the  wooden  pattern 
to  the  hignest  possible  degree  of  smoothness  and  true- 
ness  by  means  of  emery-paper,  etc.,  to  give  it  a  coating 
of  melted  parafifme  wax,  and  polish  the  surfaces  carefully 
with  a  roll  of  flannel.  This  renders  the  surfaces  not  only 
extremely  smooth  b*t  impervious  to  moisture,  so  that  the  pat- 
tern does  not  warp  or  swell  when  placed  in  the  sand.  In 
order  that  the  pattern  should  come  clean  out  of  the  sand  and 
not  break  away  any  portion  of  the  mold,  care  must  be 
taken  that  the  edges  be  slightly  rounded,  so  as  to  give  what 
is  technically  called  clearance.  The  possessor  of  a  lathe  can 
turn  up  many  portions  of  the  fittings  with  much  greater  accur- 
acy and  rapidity  than  one  provided  with  only  ordinary  tools ; 
but  in  the  ensuing  directions  the  amateur  is  supposed  to  pos- 
sess tools  of  the  simplest  kind  only.  ^ 

$  19.  The  pattern  for  the  armature  first  demands  our  at- 
tention. When  completed,  it  presents  the  appearance  shown 
at  Fig.  13,  a  being  the  elevation  and  b  the  section,  on  a  scale 
of  about  half  the  real  size,  and  consists  of  a  wooden  cylinder 
i^  inches  in  diameter  by  3^  inches  in  length,  with  a  deep 
channel  round  the  ends  and  sides.  To  construct  this  pattern, 
procure  a  piece  of  pine  8  inches  long  by  \l/2  inches  wide  and 
^  of  an  inch  thick.  Lay  this  on  a  table  on  its  widest  side, 
and  draw  a  line  along  its  whole  length,  that  shall  divide  it 
into  two  halves  of  ^  of  an  inch  each.  Now,  draw  a  line  on 
each  side  of  this  central  line,  rather  better  than  y&  of  an  inch 
from  it.  Holding  a  metal  rule  against  one  of  these  side  lines, 
with  a  sharp  penknife,  cut  into  the  wood  along  the  line  to  a 
depth  of  about  Y%  of  an  inch — rather  less  than  more.  Now, 
perform  the  same  operation  on  the  other  side  line  to  the  same 
depth.  With  a  sharp  yz  inch  chisel,  shave  away  the  wood 
on  the  outside  of  the  cut  lines  to  the  depth  of  ^  of  an  inch 
on  the  outsides,  but  rising  up  very  slightly  toward  the  center, 
as  shown  at  Fig.  13,  c.  This  precaution  will  ensure  the 
pattern  lifting  out  clear  from  the  mold. 


500 

Now,  take  a  piece  of  stout  cardboard,  and  with  a  pair  of 
compasses  strike  out  a  circle  \l/2  inches  in  diameter.  Cut  the 
circle  out  of  the  cardboard  so  as  to  leave  a  clean  circular 
aperture  of  the  diameter  specified.  Tins  is  to  serve  as  the 
templet,  or  gauge,  of  the  size  and  general  truth  of  our  arma- 
ture. Strike  out,  also,  in  a  similar  manner  a  circle  in 
a  piece  of  stoutish  zinc,  or  tinned  iron,  also  \y2  inches 
in  diameter,  and  cut  this  into  halves  (one  of  which  is  shown 


at  d\.  These  will  serve  to  shave  away  the  last  ^  irreg- 
ularities  from  the  wood,  when  it  has  been  roughly  trimmed 
up  to  the  shape  shown  at  e,  by  means  of  a  small  plane,  or 
penknife.  The  piece  may  now  be  cut  into  two  halves  across 
its  length,  doweled  and  fastened  together  with  glue,  and  cut 
down  to  the  exact  length  required  —  namely,  3^  inches. 
All  roughnesses  should  now  be  carefully  sand-papered,  and 
care  should  be  taken  that  the  finished  pattern  should  pass 
exactly  through  the  cardboard  pattern,  being  appreciably 


neither  thicker  nor  thinner  at  any  part.  When  this  has  been 
effected  satisfactorily,  a  small  quantity  of  paraffine  wax  (a 
piece  of  paraffine  candle  will  do)  should  be  melted  in  an 
iron  spoon,  and  well  rubbed  into  the  pattern  at  all  points 
with  a  roll  of  flannel  until  it  is  thoroughly  impregnated  with 
the  wax;  rubbing  the  pattern  until  it  acquires  a  polish  com- 
pletes the  operation,  and  renders  it  ready  for  the  founder. 
The  thin  central  portion,  which  joins  the  semi-circular  por- 
tions, should  be  about  2^  inches  in  length,  having  rather  * 
more  than  yz  an  inch  cut  away  at  each  end,  so  that  the  chan- 
nel is  continuous  round  the  armature,  being  ^  of  an  inch 
wide  and  about  ^  an  inch  deep  all  round. 

§  20.  The  pattern  for  the  legs  of  the  electro-magnet  (field 
magnet  s>  exciting  magnets}  will 
next  require  our  care.  Since 
the  two  legs  are  exact  counter- 
parts, the  one  of  the  other,  so 
we  need  only  make  one  pattern, 
from  which,  however,  two  cast- 
ings must  be  obtained.  Fig.  14 
illustrates  the  form  and  dimen- 
sions of  this  pattern  on  a  scale 
of  about  one-quarter  the  real 
size.  The  dimensions  are 
marked  in  inches.  A  represents 
the  outside  view,  i.e.,  as  seen 
from  the  side  which  is  farthest 
from  the  armature;  B  gives  the 
view  from  the  inside  (close  to 
which  the  armature  rotates). 
To  make  this  pattern,  procure  a  piece 
of  pine  6  inches  in  length,  4  inches  in 
width,  and  j£  an  inch  thick,  planed  smooth, 
and  free  from  knots  and  roughness.  Glue 
the  dowel  along  the  bottom  edge  a  strip 
\Y%  inch  wide,  4  inches  long,  and  J^  of 
an  inch  thick,  as  shown  at  Fig.  15,  a. 
Now,  with  a  sharp  plane,  remove  half" 
the  inner  edge,  as  shown  at  Fig.  15,  6, 
so  that  it  makes  an  angle  with  the  edge 
of  the  6-inch  piece.  With  a  fine  saw 
cut  a  recess  on  each  side  of  the  jointed 
piece  i%  inches  long  by  4  inches  deep, 


502 

as  shown  at  <r,  and  glue  and  dowel  in  each  recess  the  two 
flanges,  made  of  j^-inch  stuff,  of  the  shape  and  dimen- 
sions given  at  d.  To  insure  the  slot  e  being  exactly  at  the 
same  point  in  each  flange, the  two  flanges,  after  being  roughly 
shaped  with  a  fretsaw,  or  other  wise,  should  be  clamped 
together,  and  the  finishing  touches  given  with  a  rat-tail  file, 
for  the  slot  ey  and  with  sandpaper  along  the  rounded  edges. 
Care  must  be  taken  that  these  flanges  should  be  a.  trifle  thin- 
»ner  near  the  edge  marked  1%  than  on  the  opposite  edge,  to 
insure  the  pattern  coming  out  clean  from  the  mold.  For 
this  reason  the  slot  e  must  not  be  narrower  at  the  outside 
than  at  the  inside,  but  rather  the  contrary.  The  slot  e  must 


be  y  of  an  inch  wide,  and  must  reach  in  depth  to  the  6-inch 
piece,  to  which  the  flanges  are  attached.  At  this  point  our 
pattern  will  present  somewhat  the  appearance  shown  aty.  A 
piece  of  wood  4  inches  long  by  ij£  inches  wide,  and  #  of 
an  inch  thick,  perfectly  smooth,  square,  and  free  from  knots, 
must  now  be  chosen,  and  the  two  sides  planed  away,  on  the 
upper  side  to  such  an  extent  as  to  make  an  angle  of  60°  with 
the  base.  (See  Fig.  17,  a.)  With  some  good,  thin,  hot  glue 
this  piece  is  to  be  glued  along  the  bottom  edge  of  the  6-inch 
piece,  on  the  side  opposite  the  flanges,  and  in  such  a  manner 
that  the  slope  of  the  base  is  continued  by  the  slope  of  the 
piece,  as  shown  at  P'ig.  17,  b.  When  the  glue  is  quite  dry, 
by  means  of  an  inch  gouge,  cautiously  hollow  out  along  the 
entire  length  of  this  piece,  in  a  simicircular  form,  nearly  to 


5°3 

the  depth  of  the  original  6-inch  piece,  so  as  to  fit  accurately 
the  pattern  of  the  armature  which  has  already  been  made. 
(§  19-)  When  this  is  as  true  and  smooth  as  it  can  be  made 
with  the  gouge,  fold  a  piece  \?f  fine  glasspaper  over  the  pat- 
tern of  the  armature,  rough  side  outward,  lay  the  armature 
in  the  channel,  and  work  it  backward  and  forward  until  per- 
fect smoothness  and  a  perfect  fit  are  insured.  The  pattern 
should  now  present  the  appearance  given  at  Fig.  17,  c. 
When  this  end  has  been  attained,  four  small  dowels  should 


be  inserted  into  the  thicker  portions  of  this  semicircular  piece, 
to  hold  it  firmly  down  to  the  6-inch  piece.  We  now  need 
only  make  the  top  flange,  by  which  the  bracket  or  stand- 
ard that  bears  the  wheel  is  clamped  to  the  legs  of  the  dyna- 
mo. This  is  made  most  easily  in  two  pieces,  one  being 
squared  up  to  4  inches  long,  ^  of  an  inch  thick  by  $  of  an 
inch  wide.  The  other  piece  is  to  be  ^  of  an  inch  thick, 
and  must  be  cut  into  a  perfect  semicircle,  with  a  radius  of 
I  j£  inches.  By  means  of  glue  and  a  couple  of  dowels,  this 
is  neatly  attached  to  one  side  of  the  other  square  piece,  as 


504 

illustrated  at  Fig.  17  d,  and  then  the  whole  is  carefully  and 
squarely  glued  and  doweled,  in  like  manner,  to  the  top  of  the 
6-inch  piece,  so  that  it  now  presents  the  appearance  shown  at 
A  and  B,  Fig.  14.  The  holes  shown  in  the  bottom  and  top 
flanges  may  be  bored,  and  core  prints  inserted,  if  the  founder 
will  take  the  trouble  to  put  them  in  his  mold;  but,  as  a  rule, 
founders  do  not  care  to  cast  small  castings  with  holes  in 
them,  as  they  seldom  come  true,  so  that  it  will  be,  perhaps, 
as  well  to  have  them  bored  afterward,  which  can  be  done  at 
a  small  cost.  This  pattern  must  now  be  carefully  smoothed, 


the  sharp  edges  rounded,  to  insure  parting  from  the  mold, 
and  finally  parafined  and  polished,  as  recommended  for  the 
armature  (^  19),  when  it  will  be  ready  for  the  molder. 

§21.  The  next  pattern  to  be  made  is  that  of  the 
standard,  which  supports  the  driving-wheel.  This  should 
be  made  out  of  ^-inch  stuff,  a  piece  of  which  5^  inches 
long  by  2)4  inches  wide  must  be  cut  to  the  shape  shown 
at  A,  Fig.  1 6*  (one-quarter  the  real  size).  In  order  not  to 
split  the  top  while  boring  the  hole,  it  is  as  well  to  bore  the 
hole  (which  should  be  yz  an  inch  in  diameter)  before  shaping 
the  piece.  •#  For  the  same  reason,  the  piece  marked  C,  which 
should  be  ^  an  inch  thick  and  i  inch  in  diameter  when  fin- 
ished, should  be  glued  to  the  center  of  the  top  end  of  the  piece 
A,  and  the  whole  bored  (by  means  of  a  brace  and  sharp  l/2  -inch 


505 

center-bit)  oefore  trimming  up  to  shape.  From  the  same 
#-inch  stuff,  another  piece,  figured  at  B,  is  cut  out,  being 
y2  an  inch  wide  at  the  top,  sloping  gradually,  and  becoming 
wider  to  about  half  its  length  (d)  when  it  should  sharply 
curve  to  a  width  of  4  inches.  The  length  of  this  piece  should 
be  5  inches,  and  it  is  to  be  glued  and  doweled  to  the  center 
of  the  piece  A,  close  against  the  boss  C,  as  shown  at  B.  A 
small  piece  e  must  now  be  glued  and  doweled  to  the  edge  of 
the  curved  flange,  so  as  to  make  it  flush  with  the  front  A. 
When  this  has  been  smoothed  and  polished  with  paraffine,  the 
patterns  are  ready  for  the  foundry.  The  three  holes  shown 
at  d  may  be  bored  in  the  castings. 

THE  CASTINGS. 

§  22.  The  patterns  may  now  be  sent  to  the  foundry,  with 
the  following  instructions:  First,  the  armature  should  be 
carefully  annealed,  so  as  to  constitute  a  malleable  iron  casting; 
second,  two  legs  should  be  cast  from  the  pattern  shown  at 
Fig.  14,  and  these  also  must  be  carefully  annealed,  and  be 
made  as  soft  as  possible;  third,  the  standard  (Fig.  17,  B) 
will  be  better  if  left  pretty  hard,  as  in  this  way  it  will  retain 
sufficient  magnetism  to  start  the  machine  without  adventitic  as 
aid.  Particular  stress  must  be  laid  on  the  importance  of  the 
iron  in  the  arflflfture  and  legs  being  very  soft,  since  much  of 
the  efficiency  of  the  dynamo  will  depend  on  this  point.  (See 
§9.)  When  the  castings  return  from  the  foundry,  their 
degree  of  hardness  may  be  tested  by  trying  with  a  rather 
coarse  file.  If  the  file  bites  easily,  the  iron  is  fairly  soft;  if 
it  slips  over  without  filing,  it  is  altogether  too  hard.  (This 
does  not  apply  to  the  standard,  which  may  be  left  quite  hard 
without  any  detriment  to  the  machine).  The  armature  must 
now  be  cleaned  and  trued  up.  If  the  student  be  the  happy 
possessor  of  a  lathe,  this  will  not  prove  a  difficult  job;  if  other- 
wise, he  may,  by  careful  filing,  remove  any  irregularities,  and 
square  up  the  ends.  These  must  be  made  quite  true;  other- 
wise it  will  be  impossible  to  center  the  armature  so  as  to 
rotate  it  between  the  poles  of  the  magnet.  The  thin  central 
portion  shown  at  a,  Fig.  13,  and  there  marked  2^,  must 
have  its  edges  rounded,  so  as  not  to  cut  the  wire,  which  will 
have  to  be  wound  round  it.  No  trouble  should  be  spared  to 
get  the  armature  as  truly  cylindrical  as  possible;  as  care  ex- 
pended at  this  portion  of  the  process  will  render  the  remainder 
of  the  work  very  much  easier,  and  more  satisfactory.  The 


506 

armature  having  been  thus  rendered  true,  the  legs  will  demand 
our  attention.  Having  gone  over  the  surface  with  a  bastard 
file  to  remove  any  irregularities,  the  curved  channels,  shown 
at  A  and  B,  Fig.  14,  must  be  carefully  cleaned  out.  Perhaps 
the  quickest  way  to  do  this,  and  to  clean  the  armature  at  the 
same  time,  is  to  lay  the  two  pieces,  channels  uppermost,  on  a 
table,  putting  a  little  fine  sand  and  water  in  the  channels,  and 
then  to  work  the  armature  up  and  down  the  channels,  first  in 
one  and  then  in  the  other,  alternating  also  the  sides  of  the 
armature,  until  the  channels,  as  well  as  the  external  surfaces 
of  the  armature,  are  rendered  quite  smooth  and  bright.  The 
sharp  corners' of  the  legs  of  the  magnets  around  which  the 
wire  has  to  be  coiled  must  also  be  rounded,  and  the  top  semi- 
circular  flanges,  between  which  the  standard  has  to  be  clamped, 
must  be  filed  quite  flat  on  their  inner  surfaces,  and  made  per- 
fectly parallel  with  the  portions  marked  3^  B,  Fig.  14.  The 
standard  must  also  be  cleaned  in  like  manner,  particular  care 
being  taken  that  the  two  sides  of  the  piece  marked  B,  Fig. 
16,  be  perfectly  parallel.  The  edges  of  the  front  piece  e  must 
be  made  perfectly  square  and  true,  so  as  to  fit  exactly  on  to 
the  top  of  the  two  legs  of  the  magnets,  Fig.  14. 

§  23.  Before  winding  the  armature  and  field-magnets  with 
the  wire  in  which  the  electricity  is  at  once  generated  and  con- 
ducted, it  is  necessary  to  fit  together  accurately  the  different 
portions,  and  mark  tJiem,  so  as  to  be  able  to  put  them  together 
again  in  precisely  the  same  position  after  winding;  since  no 
filing  or  fitting  can  be  attempted  on  the  castings  after  the 
wire  has  been  wound  without  almost  certain  destruction  of  the 
insulation,  and  certain  ruin  to  the  neat  appearance  of  the 
evenly-laid  wire. 

The  part  that  calls  for  the  greatest  care  and  attention  is  the 
armature,  which,  as  it  must  rotate  in  very  close  proximity  to  the 
poles  of  the  field-magnets  at  a  rate  varying  from  1,000  to  3,000 
revolutions  per  minute,  requires  to  be  centered  most  accurately 
on  its  bearings  or  trunnions.  This  to  the  possessor  of  a  lathe 
presents  but  little  difficulty;  for  the  benefit  of  those  who  de- 
pend OR  ordinary  tools  only,  the  following  method,  by  which 
the  armature  can  be  mounted  on  its  bearings  in  a  fairly  accu- 
rate manner,  is  described.  With  a  pair  of  calipers,  the  diam- 
eters of  the  two  opposite  extremities  of  the  armature  are  taken. 
(If  the  armature  casting  were  finished  up  quite  exactly, 
these  two  measurements  would  be  exactly  alike,  viz.,  a  trifle 
under  \V2  inches  each.  But  unless  turned  on  the  lathe,  it  is 


507 

very  rare  to  get  such  precision.)  Two  circles,  of  exactly  the 
same  diameters  as  the  two  extremities  of  the  armature,  are 
now  to  be  struck  out  of  a  piece  of  hard  sheet  brass,  %  of  an 
inch  thick,  care  being  taken  to  mark  the  center  and  the  cir- 
cumference in  an  exact  and  bold  manner  with  the  compasses. 
These  circles  will  have  to  be  cut  out  of  the  brass  with  a  saw 
or  file,  so  as  to  get  two  discs,  filing  each  one  to  its  respective 
armature  extremity;  but  before  cutting  out  the  circles  thus 
marked,  three  holes  should  be  drilled  in  each,  viz.,  one  in 
the  exact  center  -J-  of  an  inch  in  diameter,  which  is  to  take 
the  driving  shaft  or  trunnion,  and  one  on  each  side  of  this 
center,  y$  of  an  inch  in  diameter,  to  admit  the  screws  which 
serve  to  attach  these  heads  or  discs  to  the  iron  portion  of  the 
armature.  Besides  these  three  holes,  which  are  common  to 
both  "heads,"  another  pair,  also  %  of  an  inch  in  diameter, 
must  be  drilled  in  one  of  the  heads,  to  allow  the  ends  of  the 
wire  which  is  to  be  coiled  around  the  armature  to  emerge 
from  them,  and  pass  through  to  the  commutator.  All  these 
holes  are  shown  full  size,  and  in 
their  correct  position  at  Fig.  18, 
where  a  is  the  central  aperture,  to 
take  the  shaft;  If  b  the  two  holes 
to  admit  the  screws,  whereby  the 
heads  are  attached  to  the  arma- 
ture;  and  c  c  holes  drilled  in  one 
head  only,  to  admit  of  the  passage 
of  wires  to  the  commutator. 
These  holes  being  bored,  and  the 
discs  accurately  cut  out,  two  pieces 
of  hard-drawn  iron  wire  (not  galvanized)  ^  of  an  inch  diameter 
and  2  inches  long,  are  carefully  straightened,  and  by  means  of 
a  screw-plate,  a  thread  is  put  on  one  end  of  each.  With  the 
corresponding  tap,  a  female  screw  is  cut  in  the  central  hole 
of  each  brass  disc.  "The  two  iron  rods  are  then  screwed  in, 
particular  care  being  taken  that  they  enter  perpendicularly 
and  centrally.  They  must  be  screwed  in  until  they  just  pro- 
trude through  to  the  other  side;  then  the  long  end  being 
allowed  to  slip  between  the  jaws  of  a  vise,  while  the  disc 
rests  flat  upon  the  surface  of  the  jaws,  a  few  steady  blows 
with  a  flat-pened  hammer  will  spread  the  bead  of  the  screw 
end  of  the  iron  rod,  so  as  to  rivet  it  firmly  to  the  disc,  and 
thus  prevent  it  working  out.  To  render  assurance  doubly 
sure,  a  drop  or  two  of  soft  solder  may  be  run  round  the  flat 


508 

side  of  the  end  of  the  rod  and  disc.  Now  we  come  to  a  part 
of  the  work  that  very  few  amateurs  can  do  at  home — viz., 
drilling  the  holes  in  the  faces  of  the  armature.  Any  black- 
smith will,  however,  do  this  for  a  few  cents.  Four  holes  are 
required,  two  at  each  end  of  the  armature  (one  end  is  shown 
real  size  at  d  d),  and  these  holes  must  be  tapped  with  a 
female  screw,  so  as  to  take  the  screws  which  serve  to  unite 
the  whole  together.  It  will  be  well  to  let  the  blacksmith 
drill  and  tap  these  holes  to  any  sized  screw  that  he  has  near- 
est approaching  %  of  an  inch  in  diameter.  Now  will  be 
also  the  time  to  get  the  blacksmith  to  drill  the  three  holes, 
right  through  the  top  end  of  the  legs  and  standard,  which 
serve  to  allow  these  portions  to  be  clamped  together  by 
means  of  bolts  and  nuts.  These 
holes  should  be  about  ^  °f  an 
inch  in  diameter.  Further  de- 
tails as  to  position  and  size  will 
be  given  a  little  farther  on.  If 
our  work  has  been  properly  per- 
formed, the  heads  may  now  be 
screwed  down  to  the  armature 
with  flat-headed  screws,  which 
should  project  about  -^  of  an 
inch  above  the  level  of  the  disc. 
Fig.  19  gives  a  representation  of 
the  finished  armature  about  half 
the  real  size. 

§  24.  Our  next  proceeding  is 
to  clamp  together  the  stand- 
ard, or  bracket,  which  serves  to  support  the  wheel  to 
the  two  legs  of  the  field- magnets.  At  the  concluding 
portion  of  $  23,  we  adverted  to  the  advisibility  of  getting 
the  holes  bored  right  through  the  top  end  of  the  legs 
and  standard,  at  the  same  time  that  the  holes  were 
being  drilled  in  the  armature.  The  position  of  these  holes 
f  is  indicated  at  Fig.  20;  they  should 
*'*'  be  about  %  of  an  inch  in  diameter,  and 
,  the  two  lower  ones  should  be  at  least  •% 
of  an  inch  from  the  bend  of  the  flange, 
,  so  as  to  allow  the  nuts  to  be  easily  turned 
and  tightened  up.  These  two  bottom 
holes  should  be  about  two  inches  apart, 
while  the  upper  one  should  sUnd  equi- 
distant from  the  others,  but  at  about  ^ 


5°9 

an  inch  from  the  top  of  the  flange.  The  amateur  will  find  at 
any  hardware  store,  very  neat  skate-screws  with  nuts  to  fit, 
of  the  form  illustrated  at  Fig.  21.  These  screws  have  usually 
rounded  heads,  without  the  slot  for  the  screw-driver  to  enter; 
but  these  can  be  easily  cut  with  a  metal  saw.  Of  course, 
any  small  bolts  and  nuts  hav- 
ing a  section  of  about  #  of  an 
inch  will  do,  but  the  ones  men- 
tioned are  very  neat  in  appear- 
ance. The  holes  being  drilled 
and  the  bolts  and  nuts  chosen, 
the  bracket  and  limbs  of  the 
field-magnet  may  be  tempo- 
rarily clamped  together,  in 
order  to  see  what  opening  is 
left  between  the  legs  for  the 
armature  to  turn  in,  at  a,  Fig. 
22.  In  all  probability  some 
filing  of  the  faces  of  the  flanges 
and  of  the  bracket  will  be  nec- 
essary to  insure  a  proper  fit. 
A  well-fittedarmature,  if  placed 
in  the  center  of  the  channels  at 
a,  should  leave  a  space  of  a  trifle  more  than  ^^Df 
an  inch  to  turn  in;  that  is  to  say,  there  should  be  ratner 
more  than  -}$  of  an  inch  clear  space  all  round  between  the 
armature  and  the  field-magnets.  Perhaps  the  quickest 
way  to  insure  this  distance  being  obtained  is  to  roll 
tightly  a  single  fold  of  stout  brown  paper  round  the 
armature  and  seal  down  the  edge  to  prevent  it  slipping;  then 
having  inserted  the  armature  in  the  channels,  to  file  away  at 
the  inner  faces  of  the  flanges,  either  toward  the  lower  por- 
tions at  b  b,  if  the  channels  are  too  wide  apart,  or  at  the 
upper  extremities  at  c  <r,  if  too  close,  until  the  whole  fits 
accurately  together.  It  is  needless  to  remark  that  when  the 
armature  thus  wrapped  in  paper  is  placed  between  the  field- 
magnets,  to  obtain  a  correct  fit,  the  solid  portions  of  the 
armature  should  lie  against  the  legs,  and  not  the  portion  of 
the  armature  which  is  hollowed  out  for  the  reception,  of  the 
wire.^.  (See  Fig.  22.) 

$25.  The  magnets  and  brackets  being  thus  properly 
clamped  together,  the  hole  in  the  top  of  the  bracket  (which 
ought  to  have  been  left  in  the  casting,  but  if  not  may  be 


5io 

bored  now)  should  be  cleaned  out  to  ^  an  inch  in  diameter. 
When  this  is  done,  two  pieces  of  hard  rolled  brass  sheet  % 
of  an  inch  thick,  6  inches  long  by  I  inch  wide,  must  be  cut 
out  and  squared  up.  One  of  these,  which  we  shall  for  the 
future  call  the  "  back  bearing,"  and  which  must  be  made  to 
fit  that  end  %of  the  dynamo  at  which  the  driving  wheel  is  to 
be  placed,  and  which  we  shall  henceforward  call  the  "  back  * 
of  the  dynamo,  is  to  be  bent  four  times  at  right  angles,  as 
shown  at  Fig.  23,  a,  where  the  dimensions  are  given.  In 

Fig.  £8. 

3fr  inches. » 


* 


<JU 

mmmm 

& 

A 

o 


order  not  to  crack  the  brass  while  bending  to  shape,  it  will 
be  well,  after  having  given  the  general  form  by  bending 
gently  and  gradually  over  the  jaws  of  a  vice,  to  heat  the 
bends  over  the  flame  of  a  spirit-lamp  until  nearly  red  hot, 
and  then  to  hammer  up  more  exactly  to  shape,  repeating  the 
heating  after  each  hammering  until  the  desired  sharpness  of 
outline  ha«;  been  obtained. 


When  this  object  has  been  attained,  another  almost  similar 
bearing  is  formed  out  of  the  remaining  piece  of  sheet  brass, 
the  principal  difference  being  that,  as  this  is  to  be  the  front 
bearing,  between  which  the  commutator  will  have  to  turn, 
a  much  greater  depth  must  be  given  to  the  central  bent 
portion,  as  may  be  seen  at  Fig.  23,  b,  the  dimensions  being 
given  in  inches  as  before.  When  the  brass  has  been  bent 
to  these  forms,  the  bearings  thus  produced  should  be  laid 
each  against  its  own  respective  end  of  the  dynamo,  in  such 
a  position  that  the  center  of  the  bend  comes  in  the  center 
of  the  channel,  the  two  flat  extensions  lying  close  to,  and 
flat  against,  the  slotted  lugs  shown  at  Fig.  22,  d  d.  The 
bearings  should  now  be  cut  in  a  sloping  fashion  to  follow  the 
outline  of  the  lugs,  as  shown  at  Fig.  23,  c  ;  but  the  outline 
of  the  slotted  portion  should  not  be  followed,  as  a  J^-inch 
hole  must  be  drilled  in  the  brass  at  this  point  to  take  a 
5-inch  bolt  and  nut.  The  exact  position  of  these  holes  may 
be  obtained  by  holding  each  bearing  in  succession  against  its 
own  proper  extremity,  and  scratching  with  a  steel  point  on 
to  the  brass  the  position  in  which  the  slots  in  the  lugs  fall ; 
hen,  with  a  Morse  twist  drill,  a  ^-inch  hole  can  be  drilled 
at  each  extremity  nearest  to  the  center  of  the  bearing,  as 
shown  at  Fig.  23,  d. 

Having  got  so  far,  let  us  clamp  the  back  bearing  in  its 
place  by  means  of  two  bolts  about  5  inches  long,  passing 
through  the  holes  in  the  bearings  and  through  the  slots  in 
the  lugs,  held  in  their  places  by  two  nuts  screwed  down  on 
to  the  front  lugs  of  the  dynamo.  Taking  the  armature  in 
one  hand,  we  roll,  as  before,  one  fold  of  paper  round  it,  and 
put  a  dot  of  Brunswick  black  on  the  extremity  of  the  trun* 
nion  rod  at  the  back  end  of  the  armature  (the  end  where  the 
holes  are  bored  for  the  wire  to  come  out  is  the  front,  the 
other  is  the  back),  and  then  insert  it  into  the  channel 
between  the  legs  of  the  field-magnets,  until  the  trunnion  rod 
on  shaft  touches  the  brass  forming  the  back  bearing.  In  so 
doing  it  will  leave  a  mark  of  Brunswick  black,  which  will  be 
the  point  at  which  a  #-inch  hole  must  be  bored.  This 
must  be  done  most  carefully,  so  as  to  preserve  centricity ; 
and  when  done  must  be  rimed  out  and  bushed  with  a  piece 
of  brass  tubing  of  about  -^  external  diameter,  the  internal 
diameter  of  which  must  exactly  correspond  with  the  external 
diameter  of  the  driving-shaft  or  trunnion  of  the  armature  ;  in 
fact,  this  latter  must  fit  exactly  into  the  tube,  without  any 


shake.  This  piece  of  tubing  should  be  about  i#  inches  in 
length,  and  should  be  soldered  into  the  central  hole  in  the 
back  bearing,  and  should  extend  inward  to  such  a  degree 
that  when  the  back  bearing  is  clamped  in  its  place,  with  the 
armature  in  its  position,  with  the  back  trunnion  in  the  tube, 
and  the  back  head  flush  with  the  back  of  the  magnets,  it 
should  just  rest  against  the  back  head  of  the  armature. 


In  a  precisely  similar  manner  the  center  of  the  front 
bearing  is  found ;  that  is  to  say,  the  back  bearing  being 
removed,  the  front  bearing  is  clamped  to  the  front  of  the 
dynamo,  the  armature,  rolled  in  one  fold  of  paper,  is  inserted 
from  the  back  end  of  the  dynamo,  front  end  forward,  and 
care  taken  to  moisten  the  front  end  of  the  driving- shaft  with 
Brunswick  black  or  other  color,  so  as  to  get  a  mark  where 
it  touches.  The  hole  being  drilled  and  rimed  out,  as  in  the 
previous  case,  is  to  be  likewise  bushed  with  the  same  kind  of 


brass  tubing  ;  but  in  the  front  bearing,  the  tube  should  be 
only  flush  with  the  inside  of  the  bearing,  and  sJiould  not 
extend  in  toward  the  armature. 

§  26.  The  Commutator 'next  claims  our  care.  This  essen- 
tial piece  of  apparatus  serves,  as  the  student  may  remember 
(^  12),  to  rectify,  or  send  in  one  direction,  the  vibrations  or 
currents  which  are  produced  in  opposite  directions,  as  each 
pole  of  the  armature  passes  alternately  before  the  north  and 
south  pole  of  the  field-magnets.  In  screwing  the  brass  heads 
down  to  the  armature,  the  student  was  advised  (§  23,  Fig.  19) 
to  employ  flat-headed  screws,  projecting  about  §  of  an  inch 
above  the  level  of  the  discs.  The  use  of  the  projecting 
heads  is  to  prevent  the  commutator  slipping  round  the  axis 
or  trunnion  of  the  armature  when  the  latter  revolves.  The 
body  of  the  commutator  may  be  turned  up  out  of  a  piece  of 
sound  boxwood,  which  previous  to  turning  up  should  have 
been  allowed  to  soak  for  a  couple  of  hours  in  melted  parafrine. 
It  should,  when  finished,  present  the  appearance  shown  at 
Fig.  24,  a.  While  on  the  lathe,  a  hole,  perfectly  central, 
should  be  drifted  right  through  it,  into  which  the  front  shaft 
or  trunnion  of  the  armature  fits  tightly.  The  length  of  this 
should  be  1 2  of  an  inch,  so  that  it  just  clears  the  front  bearing 
when  in  its  place.  The  diameter  should  be  about  |-ofan 
inch,  so  that  the  two  flat-headed  screws  of  the  front  arma- 
ture head  should  be  covered  by  the  cylinder  on  opposite 
sides  of  its  circumference  to  the  extent  of  about  }/%  of  an  inch. 
Two  semicircular  nicks  must  be  cut  out  of  the  bottom  of  the 
cylinder  to  allow  these  screw  heads  to  enter,  so  that  the 
cylinder  when  driven  home  rests  quite  against  the  disc  or 
head.  The  front  of  this  cylinder  (the  part  farthest  from  the 
disc)  must  be  rounded  slightly,  so  as  not  to  present  too  great 
a  surface  for  friction  against  the  front  bearing.  A  piece  of 
brass  tube,  ^  of  an  inch  shorter  than  the  cylinder,  and  of  such 
internal  diameter  as  to  fit  tightly  on  it,  is  now  cleaned  up  and 
cut  into  two  exactly  equal  halves  longitudinally.  The  cuts 
must  not  be  quite  parallel  to  the  axis  of  the  cylinder,  but 
must  make  a  small  angle  with  it,  in  order  that  the  "  brush  " 
or  spring  which  takes  the  current  off  the  commutator  should 
at  no  time  abruptly  leave  one  half  tube  before  it  rests  on  the 
other;  otherwise  the  commutator  sparks  badly  while  at  wrork, 
and  the  sparks  injure  both  commutator  and  brushes,  besides 
entailing  loss  of  current.  The  amount  of  angular  deviation 
from  the  line  of  axis  should  not,  in  this  machine,  exceed  two 


or  three  degrees  of  arc,  and  care  must  be  taken  they  are 
equi -distant,  and  both  inclined  in  the  same  direction.  To 
insure  this,  stand  the  tube  (already  cut  to  length  and  cleaned) 
on  one  end.  Take  the  exact  diameter  with  a  pair  of  com- 
passes, and  strike  out  on  a  piece  of  card  a  circle  of  exactly 
similar  diameter.  Rule  two  fine  lines  across  this  circle,  both 
cutting  the  center,  but  exactly  ^  of  an  inch  apart  at  the  cir- 
cumference, like  a  letter  X.  Lay  this  card  on  the  top  of  a 
tube,  and  with  a  steel  point  or  file  make  a  mark  on  the  rim 
of  the  tube  at  each  of  the  points  where  the  lines  touch  the 
circumference  of  the  circle.  Now  lay  the  tube  on  its  side, 
and  draw  four  lines  straight  along  the  length  of  the  tube, 
starting  from  the  points  just  marked.  Fach  opposite  pair  of 
lines  will  be  exactly  £  of  an  inch  apart,  and  quite  parallel. 
Having  done  this,  bring  one  pair  of  lines  uppermost,  and 
draw  a  diagonal  line  from  the  top  of  the  right  hand  to  the 
bottom  of  the  left-hand  line.  Now  turn  the  tube  half  a  rev- 
olution, so  as  to  bring  the  lower  pair  of  lines  uppermost,  and 
draw  a  similar  diagonal  line,  in  the  same  direction-  viz. , 
from  the  top  of  the  right  hand  line  to  the  bottom  of  the  left- 
hand  line.  Now,  with  a  fine  fretsaw  cut  the  tube  into  two 
halves  in  the  direction  of  the  two  diagonal  lines  just  de- 
scribed. The  tube,  with  the  diagonal  lines  marked  ready  for 
cutting,  is  shown,  as  if  transparent,  at  Fig.  24,  b.  It  will  be 
noticed  that  though,  when  seen  through,  these  lines  cross 
each  other,  yet  when  either  portion  of  the  marked  tube  is 
uppermost  the  line  of  division  is  from  right  downward  to 
left*  The  split  tube  is  now  to  be  fastened  to  the  boxwood 

cylinder  in  such  a  position 
that  the  middles  of  the  lines 
of  division  shall  be  exactly 
in  a  line  with  the  middle  of 
the  channel  of  the  armature. 
(See  Fig.  25.)  These  two 
half-tubes  may  be  attached 
to  the  boxwood  cylinder  or 
core  by  means  of  two  short 
flat -headed  screws,  care  be- 
ing taken  that  these  screws 

•J£^J^  do  not  reach  to  make  con- 

tact with  the  trunnion  or 
touch  the  "head'  of  the 
armature.  The  split  ring, 


5*5 

when  fastened  in  its  place,  should  reach  to  within  about  ^ 
of  an  inch  of  each  end  of  the  boxwood  core;  and  if  screws 
are  used  to  fasten  it  down  these  should  be  placed  at  the  end 
nearer  the  armature.  But  another  \ery  neat  and  effective 
way  of  attaching  the  split  tube  or  ring  to  the  core  is  by  means 
of  two  narrow  ivory  or  bone  rings,  forced  over  the  split  tube, 
one  at  each  end.  Care  must  be  taken,  in  either  case,  that 
the  divisions  in  the  split  tube  are  maintained;  for,  of  course, 
if  the  two  halves  of  the  tube  were  allowed  to  touch  at  any 
point  the  current  would  flow  round  at  that  point  or  "  short 
circuit,"  and  no  current  would  be  perceptible  on  the  outside. 
To  insure  the  distance  being  maintained,  it  is  well  to  place  a 
shaving  of  paraffined  wood  of  the  same  thickness  as  the  saw- 
cuts  between  the  two  halves  of  the  split  tube  on  both  sides. 

§  27.  Those  who  have  not  a  lathe  can  make  a  very  fair 
substitute  for  the  boxwood  cylinder  by  rolling  and  gluing  a 
stout  piece  of  brown  paper/ just  as  if  making  a  rocket-case, 
around  a  piece  of  the  same  iron  rod  that  served  for  the  trun- 
nions of  the  armature,  until  a  cylinder  %  of  an  inch  thick 
and  §|  of  an  inch  long  has  been  produced.  '  This  should  be 
rolled  very  hard  while  on  the  iron  rod,  so  as  to  insure 
its  being  truly  cylindrical;  the  rod  on  which  it  was  rolled 
should  then  be  pulled  out,  and  the  tube  allowed  to  dry  thor- 
oughly. When  dry  it  should  be  soaked  for  half  an  hour  in 
melted  parafnne,  then  reared  on  end  to  drain  and  cool.  It 
will  be  found  to  work  extremely  well.  Of  course  the  split 
ring  can  be  attached  to  this,  either  by  screws  or  by  two  rings, 
as  in  the  former  case. 

§  28.  Two  rectangular  pieces  of  boxwood  (previously 
boiled  in  paraffine)  must  now  be  cut,  planed  and  drilled. 
These  are  the  "  brush  blocks,"  which  serve  to  support  the 
metalliq^prings  or  "  brushes  "  which  press  against  the  com- 
mutator. Some  operators  prefer  to  mount  their  blocks  on 
the  stand,  separate  from  the  dynamo  castings;  here  the  pfan 
followed  is  to  cause  the  bolts  which  clamp  the  bearings  to 
the  field-magnets  to  carry  the  brush  blocks.  To  this  end  the 
two  pieces  of  boxwood  should  be  cut  so  as  to  fit  exactly  the 
space  left  between  the  shoulders  of  the  front  bearings 
on  the  outside^  and  bored  so  as  to  allow  the  bolts  to  come 
right  through  to  take  the  nuts;  that  is  to  say,  the  blocks  will 
be  almost  cubical  in  shape,  being  i  inch  long,  \\  of  an  inch 
wide,  by  %  of  an  inch  thick.  Fig.  26  shows  one  of  these 
blocks  in  its  place,  clamped  to  the  bearing  by  the  nut  and  bolt. 


5*5 

$  29.  In  order  to  communicate  the  motion  from  the  fly- 
wheel to  the  armature,  a  small  pulley -wheel,  either  of  iron 
or  brass,  is  fitted  to  the  back  trunnion,  just  outside  the 
bearing.  Such  a  pulley- wheel  may  be  bought  at  any  hard- 


ware  store,  and  should  be  about  i%  inches  in  diameter,  and 
rather  over  %  of  an  inch  thick,  with  the  central  hole  some- 
what smaller  than  the  diameter  of  the  rod  which  serves  for 
the  armature  trunnion.  This 
may  be  attached  to  the  trunnion 
in  either  of  the  two  following 
ways:  ist.  By  "  keying, "which 
consists  in  filing  the  trunnion 
along  its  length  in  one  direction 
only,  so  as  to  produce  a  flattened 
side;  then,  having  with  a  rat- 
tail  file  cleaned  out  the  central 
hole  of  the  pulley  to  such  an  ex- 
tent that  the  said  trunnion  will 
only  just  enter,  to  deepen  one 
side  (corresponding  to  the 
flattened  side  of  the  trunnion)  so 
as  to  admit  of  a  small  steel 
wedge  or  "  key  "  being  inserted. 
(See  Fig.  27,  a.)  2nd.  By  filing 
the  trunnion-rod  to  a  slightly 
conical  shape,  and  producing  a 
similar  "  coning  "  in  the  interior 
of  the  pulley  hole,  which  may 
then  be  driven  on.  (See  Fig. 
27,  />,  where  the  "  coning  "of  the 
trunnior,  is  exaggerated,  to 
render  this  mode  of  attachment 
more  plainly  visible.)  Which- 


517 

ever  mode  of  attachment  is  adopted,  one  precaution  must  be 
taken  —  viz. ,  that  the  distance  between  the  back  of  the 
field-magnets  and  the  pulley  should"  not  be  less  than  i# 
inches;  otherwise,  when  the  limbs  of  magnets  are  wound  with 
wire,  the  fly-wheel  will  run  too  close  to  them  to  be  altogether 
safe. 

§  30.  The  fly-wheel  which  gives  motion  to  the  armature 
should  be  a  pretty  heavy  wheel,  about  13  inches  in  diameter, 
with  a  groove  in  the  rim  to  take  the  band  which  drives  the 
pulley,  furnished  with  a  wooden  handle  for  convenience  of 
rotating.  Such  wheels  may  be  obtained  ready  made  in  cast- 
iron,  from  most  hardware  or  agricultural  implement  dealers, 
as  they  are  sent  out  with  "rotary  blowers,"  "portable 
forges,"  etc.  Fig.  28  a  gives  an  idea  of  the  kind  of  wheel 
necessary,  on  a  scale  of  i^  inches  to  the  foot.  The  central 
hole  is  turned,  and  only  requires  fittting  with  an 
iron  pin,  on  which  it  turns.  Since  the  aperture 
in  these  wheels  is  about  ^  of  an  inch  in  diam- 
eter, the  pin  must  be  filed  down  to  yz  an  inch  diameter, 
where  it  hns  to  fit  the  hole  in  the  flange  at  the  top  of  the 
dynamo. 

The  farthest  end  should  have  a  rounded  head,  to  prevent 
the  wheel  from  working  off,  while  the  portion  which  passes 
into  the  eye  at  the  top  of  the  flange  must  have  a  thread  put 
on  it,  so  as  to  take  a  nut.  (See  Fig.  28,  b.} 

§  31.  All  the  portions  of  the  dynamo  being  now  fitted,  they 
should  be  marked  so  as  to  insure  putting  together  again  in  right 
order  after  winding.  When  this  has  been  done;  the  limbs  of 
the  field-magnets,  at  all  parts  except  the  channel  for  the  arma- 
ture, and  the  inner  face  of  the  semicircular  top  which  rests 
against  the  wheel  bracket,  should  receive  a  coat  of  good 
Brunswick-black,  allowing  them  to  dry  between  each  applica- 
tion, in  a  warm  oven.  The  bracket  should  likewise  receive 
a  coat  or  two  of  the  same  varnish,  except  where  semicircular 
tops  clinch  it.  This  portion  must  be  left  metallic,  so  as  to 
insure  magnetic  contact;  otherwise  much  magnetic  power  is 
lost.  Two  strips  of  silk  (color  immaterial)  10  inches  long  by 
3^  inches  wide,  should  now  be  quickly  brushed  over  with 
Brunswick-black,  and  wrapped,  while  still  sticky,  one  round 
the  one  limb,  and  the  other  round  the  other  limb  of  the  field- 
magnets,  in  the  space  between  the  armature  channel  and  the 
bend  at  the  top.  (See  Fig.  14,  where  the  portions  indicated 
are  marked  respectively  4"  and  3%". )  The  object  of  this  silk 


wrapping  is  to  insulate  the  wire  thoroughly  from  the  iron, 
and  to  prevent  any  accidental  abrasion  of  the  covering  wire, 
which  may  take  place  during  careless  winding  from  short  cir- 
cuiting to  the  iron  below.  When  the  silk  has  been  laid 
smoothly  and  tightly  on,  the  limbs  may  be  returned  to  the 
oven,  and  allowed  to  dry  at  a  gentle  heat.  In  precisely  the 
same  manner  the  intetior  faces  and  their  central  portion  of 
the  armature  (technically  known  as  the  "  web  ")  must  be  var- 
nished with  Brunswick-black,  and  wrapped  with  one  layer  of 
similarly  prepared  silk.  Three  pieces  will  be  required  to  do 
this  effectually — viz.,  two  pieces  3^  inches  long  by  i^ 
inches  wide,  shaped  as  in  Fig.  29,  to  fit  against  the 
inner  faces,  and  one  piece  6  inches  long,  by  ^  of  an  inch 
wide,  to  wrap  round  the  web.  Particular  care  must  be 
taken  that  every  portion  of  the  inside  of  the  armature's 
channel  be  entirely  covered  in  silk.  When  this  has  been 
satisfactorily  performed,  another  coat  of  Brunswick-black  may 
be  given  (avoiding  to  soil  the  outside),  and  the  armature 
allowed  to  dry  thoroughly  in  a  warm  oven. 

§  32.  Our  dynamo  is  now  ready  for  wiring.  For  this  pur- 
pose we  shall  require  about  7  Ib.  of  No.  16  single  cotton- 
covered  copper  wire  for  the  field-magnets,  and  about  ^  Ib. 
No.  20  double  silk-covered  for  the  armature.  The  amateur 
should  be  careful  to  get  new  wire,  of  the  highest  conductivity, 
and  very  soft;  the  employment  of  old,  kinky,  and  hard  wire 
is  fatal,  to  success. 

§  33.  The  quantity  of  wire  above  mentioned  having  been 
duly  selected,  it  should  be  tested  for  continuity.  The  No. 
16  will  give  evidence  to  the  sight  alone,  whether  there  be 
any  break  in  it  or  not.  Should  there  be  such,  the  covering 
from  the  two  broken  ends  should  be  uncovered  for  about  an 
inch  on  each  end,  the  two  extremities  filed  down  to  a  fine 
flat  wedge,  so  as  to  fit  one  another,  when  each  one  separately 
should  be  warmed  for  a  second  over  the  flame  of  a  spirit- 
lamp,  dipped  into  powdered  resin,  and  rubbed,  while  being 
held  in  the  flame  of  the  lamp,  with  a  rod  of  solder,  until 
each  has  taken  a  good  coating  of  solder.  The  two  ends  may 
then  be  applied  with  their  flattened  portions  together  over 
the  flame  of  the  spirit  lamp  until  the  solder  coating  melts. 
Keeping  the  ends  pressed  together,  the  wire  is  to  be  removed 
from  the  flame.  The  solder  soon  hardens,  and  the  wires  will 
be  found  firmly  united.  It  is  now  only  necessary  to  file 
away  any  roughness,  and  rewind  the  cotton  covering  over  the 


519 

bared  portion,  adding  a  little  darning-cotton  if  the  covering 
be  deficient.  The  finer  wire,  which  is  generally  bought  on 
reels,  had  better  be  tested  with  the  galvanometer  (Fig.  2). 
To  this  end,  find  the  two  extremities  of  the  wire,  attach  one 
to  one  binding-screw  of  the  galvanometer,  the  other  extrem- 
ity being  in  good  metallic  contact  with  the  pole  of  any  single- 
cell  battery.  Connect  the  other  pole  of  the  battery  with  the 
other  binding-screw  of  the  galvanometer.  An  immediate 
and  large  deflection  of  the  needle  will  show  that  the  wire  is 
continuous.  If  not,  the  wire  must  be  unwound  from  the 
reel,  and  carefully  wound  on  to  another  until  the  point  at 
which  the  break  occurs  has  been  discovered.  The  two  broken 
ends  maybe  joined  as  described  above,  great  care  being  taken 
after  joining  to  recover  the  point  of  junction  thoroughly,  so 
as  to  preclude  all  danger  of  leakage,  more  silk  being  used  to 
this  end  if  necessary.  It  having  been  ascertained  that  the 
wire  is  perfect  and  in  good  condition,  the  next  step  is  to  soak 
it  in  melted  paraffine  wax,  The  good  effect  of  this  is  twofold: 
(a)  The  insulation  is  thereby  rendered  very  much  better; 
(b}  a  damp  atmosphere  has  then  little  or  no  effect  on  the  in- 
sulation, since  the  paraffined  cotton  and  silk  covering  is  no 
longer  hygroscopic,  and  may  actually  be  pumped  upon  with- 
out becoming  wetted  or  spoiling  the  insulation.  To  paraffine 
nicely  the  wire  should  be  laid  in  a  shallow  dish  large  enough 
to  contain  it  easily — a  circular  tin  baking  dish  will  do  admir- 
ably. It  should  then  be  placed  in  a  warm  oven,  not  too  hot, 
until  it  is  about  the  heat  of  the  hand — say,  90°  Fahr.  About 
%  Ib.  of  good  paraffine  wax  should  now  be  placed  in  the 
tin,  and  the  oven  closed  until  the  paraffine  is  all  melted.  The 
wire  may  then  be  turned  over  two  or  three  times  until  it  is 
seen  to  be  thoroughly  soaked  with  the  paraffine.  Two  or 
three  metal  rods  should  now  be  placed  across  the  top  of 
the  dish,  on  which  the  wire  may  be  placed  to  drain  for  a  few 
seconds  while  still  in  the  oven.  When  it  ceases  to  drip  it 
may  be  removed  from  the  oven  and  allowed  to  cool.  The 
superfluous  paraffine,  while  still  hot,  may  be  poured  into 
a  cup  (which  has  been  just  previously  breathed  into)  to 
set,  when  it  may  be  used  for  other  insulations. 

1 3  j.  Winding  the  armature  next  clains  our  attention. 
Having  marked  the  heads, so  as  to  know  which  belongs  to 
a  given  extremityof  the  armature,  we  unscrew  and  remove 
them;  about  6  inches  of  the  extremity  of  the  No.  20  wire 
should  be  coiled  tightly  round  the  end  of  a  pencil,  so  as  to 


520 

form  a  tight  helix  from  which  the  pencil  must  then  be  slipped 
out.  This  helix  will  form  one  of  the  spare  ends  of  the  wire 
which  will  be  attached  to  the  commutator,  and  should  be,  for 
the  time  being,  tied  with  a  bit  of  silk  to  the  outside  of  the 
armature,  so  as  to  be  out  of  the  way  while  winding.  Hold- 
ing the  armature  in  the  left  hand,  with  the  end  which  corre- 
sponds to  the  commutator  facing  us,  and  beginning  at  the  left- 
hand  cheek,  we  wind  the  wire  in  the  channel,  continuing  to 
wind  until  we  reach  the  right-hand  cheek,  taking  care  to  lay  the 
wire  on  as  closely  as  possible,  never  allowing  it  to  ride  over 
its  neighbor,  nor  yet  to  leave  gaps  between.  When  .one 
layer  has  thus  been  carefully  wound  on,  as  shown  at  Fig.  30, 
it  should  be  tested  for  insulation,  since 
the  amateur  is  very  apt  to  wind  care- 
lessly and  cut  the  insulating  covering, 
either  by  catching  in  the  sharp  corners 
of  the  channel  or  otherwise.  To  test 
for  insulation,  tie  the  end  of  the  wire 
(without  detaching  it  from  the  reel  or 
hank)  against  one  cheek  of  the  arma- 
ture, to  prevent  its  unwinding  during 
the  trial;  then  connect  one  pole  of  a 
battery  to  one  binding-screw  of  a  gal- 
vanometer, and  the  helix  end  of  the 
wound  wire  to  the  other  binding-screw. 
On  touching  the  iron  of  the  armature  at 
any  point  with  the  other  pole  of  the  bat- 
tery, no  deflection  of  *he  needle  should 
take  place.  Should  a  deflection  show  itself,  evincing  a 
metallic  contact  and  want  of  insulation  at  some  point,  the 
wire  must  be  unwound,  the  flaw  localized  and  remedied 
by  a  fresh  covering  of  silk,  basted  with  paraffine,  and  again 
wound  on  and  tested  until  the  insulation  is  satisfactory.  A 
layer  of  thin  paraffined  paper  should  now  be  laid  over  the 
first  layer  of  wire,  and  the  winding  proceeded  with  in  exactly 
similar  manner,  until  the  second  layer  has  been  laid  on, 
remembering  that  the  essentials  of  success  are  to  wind  the 
wire  as  closely  as  possible  in  each  layer  without  overlapping; 
to  avoid  grazing  the  covering  of  the  wire,  so  as  to  maintain 
insulation,  and  to  wind  always  in  one  direction — viz.,  from 
us,  over  to  under.  There  is  no  necessity  (when  using  silk- 
covered  wire)  to  place  a  stratum  of  paraffined  paper  between 
«ach  layer  of  wire,  as  this,  by  increasing  the  distance  between 


521 

the  layers,  somewhat  decreases  the  efficiency  of  the  machine; 
this  is  only  advisable  when  the  insulation  of  the  wire  has  been 
found  to  be  imperfect.  The  winding  should  be  proceeded 
with,  layer  after  layer,  evenly,  tightly  and  smoothly,  until  the 
wire  just  fills  the  channel.  Care  must  be  taken  that  it  does  ' 
not  exceed  this,  for  if  it  comes  higher  than  the  cheeks  it  will 
surely  catch  in  the  limbs  of  the  field-magnets  during  rotation. 
From  eight  to  nine  layers  of  wire  may  be  laid  on,  according 
to  the  tightness  with  which  it  is  pulled  during  winding. 
When  the  due  proportion  of  wire  has  been  laid  on,  it  should 
be  fastened  down  by  tying,  so  as  not  to  unwind,  with  its  free 
end  at  the  same  extremity  (the  commutator  end)  as  we 
started  from.  The  helix  may  now  be  straightened  out,  and 
its  condition  observed,  to  insure  that  it  is  well  insulated. 
The  end  at  which  we  finished  winding  should  also  be 
straightened  out  and  examined  for  good  covering  Then 
a  stick  of  elastic  glue  should  be  heated  and  rtibbed 
over  the  covered  ends  right  up  to  the  armature,  so 
as  to  thicken  them  to  such  an  extent  that  they  will 
only  just  pass  through  the  holes  bored  in  the  head  to  which 
the  commutator  is  attached.  (See  Fig.  18,  c,  c,\  The 
wire  ends  should  be  passed  one  through  each  of  these  holes 
(care  being  taken  that  the  head  be  put  on  as  it  was  previous 
to  removal),  pulled  pretty  tightly,  but  not  so  roughly  as  to 
graze  or  injure  the  covering,  and  having  been  cut  so  as  to  just 
reach  the  heads  of  the  screws,  which  fasten  the  two  halves 
of  the  split  tube  of  the  commutator  to  its  cylinder  (see  Fig. 
25),  should  have  their  extreme  ends  unwound  and  cleaned, 
and  then  be  soldered  down,  one  to  each  half  of  the  split 
tube,  care  being  taken  that  neither  the  solder  nor  the  wire 
passes  beyond  the  line  of  the  screws;  so  as  to  leave  plenty 
of  room  for  the  brushes  to  press  against  the  commutator. 
The  heads  may  now  be  screwed  up  in  their  place,  and  a 
coat  of  good  sealing-wax  varnish  (best  made  by  dissolv- 
ing good  scarlet  sealing-wax  in  methylated  spirit)  painted 
over  the  layers  of  wire,  both  for  the  sake  of  appearance 
and  to  keep  the  wires  from  moving  out  of  place  during 
rotation,  though  if  the  wires  are  tightly  wound  this  would 
be  hardly  needful.  This  coat  of  varnish  must  be  allowed 
to  dry  off  in  a  warm  atmosphere  (not  in  the  oven),  and 
the  armature  will  be  complete. 

?  35.  Our  labors  are  now  drawing  to  a  close.     To  wind 
the  field-magnets  it  will  be  as  well  to  rig  up  a  little  piece  of 


apparatus,  since,  although  they  may  be  wound  without,  it 
is  very  difficult  to  lay  the  wire  as  closely,  as  tightly, 
and  as  neatly  as  can  be  done  by  its  aid;  and  since  the  effi- 
ciency of  the  machine  is  greatly  exalted  by  the  greater  proxim- 
ity of  the  wire  to  the  core,  it  is  a  matter  of  considerable 
importance  that  this  should  be  attended  to.  The  apparatus 
necessary  consists  of  a  handle  fastened  to  an  axle  passing 
through  a  standard  supported  on  a  base;  the  axle  having  a 
prolongation  to  which  each  limb  of  the  field-magnets  can  be 
screwed  down  in  its  turn.  On  turning  the  handle,  it  is  evi- 
dent that  the  iron  mass  of  the  field-magnet  will  rotate  on  its 
axis,  and  if  lare  be  taken  that  the  center  of  the  mass  coincides 
with  the  center  of  motion,  the  motion  imparted  to  the  iron 
will  be  smooth  and  even,  and  the  wire  may  be  laid  on  with 
great  exactitude  and  closeness.  This  apparatus  is  illustrated 
at  Fig.  31,  a,  with  one  of  the  limbs  of 
the  field-magnets  screwed  in  its  place, 
ready  for  winding.  It  should  be  made 
out  of  ^-inch  stuff,  the  base  being 
about  5  inches  wide  by  6  inches  long. 
The  upright  through  which  the  axle 
passes  should  also  be  about  the  same 
size,  and  screwed  to  the  edge  of  the 
baseboard,  so  as  to  stand  at  right  an- 
gles to  it.  A  short  piece  of  broomstick, 
about  ^  of  an  inch  in  diameter,  may 
be  used  as  the  axle,  and  a  hole  must  be  bored  in  the  upright, 
at  about  4  inches  from  this  base,  to  admit  this  axle.  To  the 
external  portion  of  the  axle  is  fastened  a  handle;  while  to  the 
internal  portion,  which  should  protude  about  i)4  inches,  is 
screwed  a  piece  of  J^-inch  stuff  about  i%  inches  square,  half 
the  axle  being  cut  away  to  admit  of  its  lying  flat.  Previous 
to  screwing  down,  the  handle,  as  well  as 
this  latter  square  piece,  should  be 
rubbed  over  with  a  little  good  hot  glue 
at  the  places  where  they  touch  the  axle, 
to  insure  a  good  sound  joint.  This 
*'  winder  "  being  completed,  it  may  be 
clamped  to  a  bench  or  table  by  means 
of  a  sewing-machine  or  fretsaw  clamp, 
the  leg  of  the  field-magnet  having  been 
previously  screwed  to  it  by  means  of  the 
three  holes  in  the  flange,  in  the  position 
shown  in  the  figure.  Though  shown  in 


523 

the  cut  to  the  left,  the  handle  of  the  winder  should  be  to  the 
right  of  the  operator,  unless  he  be  left-handed.  In  commenc- 
ing to  wind  the  wire,  the  operator  should  stand  over  his 
work,  a  sheet  of  paper  having  been  placed  on  the  floor,  and 
the  coil  of  paraffined  wire  at  his  feet,  with  a  two-gallon  stone 
bottle  filled  with  water,  to  keep  the  bottle  from  upsetting,  in 
the  center  of  the  coil  to  prevent  its  tangling  or  kinking.  The 
surface  of  this  jar  being  glazed,  the  wire  slips  from  it  without 
injuring  the  covering.  The  winding  should  be  commenced  at 
the  extremity  farthest  from  the  handle — that  is,  nearest  to 
the  channel  in  the  field-magnets  in  which  the  armature  ro- 
tates. Six  or  eight  inches  of  the  wire  should  be  coiled  round 
a  pencil,  and  so  as  to  form  a  tight  helix,  which,  with  a  piece 
of  strong  twine,  should  be  tied  to  the  leg  of  the  magnet,  as 
shown  in  Fig.  31,  b.  Holding  the  loose  end  of  the  wire 
in  the  left  hand,  keeping  it  pretty  tightly  pulled,  and 
straightening  it  out  from  its  coiled  shape  as  it  passes  through 
the  fingers,  it  is  easy  in  this  manner  to  wind  the  wire  per- 
fectly flat  and  smooth  by  turning  the  handle  of  the  winder  in 
the  direction  of  the  motion  of  the  hands  of  a  watch.  (In  or- 
der to  prevent  any  accidental  contact  though  abrasion  against 
the  corners,  etc. ,  it  is  advisable  previously  to  cover  the  legs 
of  the  field-magnets,  at  all  events  as  far  as  the  wire  is  to  ex- 
tend— viz.,  from  c  to  d  in  the  present  figure — with  a  band  of 
silk  dipped  in  melted  paraffine,  and  applied  hot  to  the  iron, 
when  it  will  immediately  adhere.  This  band  must  be  care- 
fully smoothed  down,  so  as  not  to  cause  unevenness  in  the 
winding  of  the  wire.)  If  the  wire  be  nicely  laid  on,  it  will 
be  found  possible  to  wind  forty  rows  between  c  and  d.  Be- 
fore arriving  at  d  it  will  be  necessary  to  place  two  pieces  of 
tape  about  ^  an  inch  wide  and  3  inches  long,  as  shown 
at  e  e  in  the  figure,  the  free  ends  of  which  must  be  turned 
back  smoothly  and  tightly  over  the  layer  just  put  on  when  d 
is  reached.  Continuing  the  rotation  of  the  handle  in  the 
same  direction,  another  layer  of  wire  is  now  laid  over 
the  first;  by  holding  the  ends  of  the  tape  fast  while 
beginning  to  wind  this  second  layer,  all  tendency  of  sinking 
into  the  layer  beneath,  which  may  be  displayed  by  the 
second  layer,  is  overcome.  Without  this  precaution  it  is 
almost  impossible  to  prevent  the  outer  layers  of  wire  sinking 
into  the  interspaces  of  the  layers  below.  Continuing  in  this 
manner,  layer  after  layer  should  be  laid  on  until  seven  layers 
have  been  wound,  remembering  to  use  tapes  toward  the  end 


524 

of  each  layer,  and  that  each  layer  will  diminish  by  two  rows. 
When  the  seven  layers  have  been  laid  on,  the  wire  must  be 
tied  down  to  the  magnet  to  prevent  uncoiling,  and  cut  off 
from  the  hank  of  wire,  leaving  about  6  inches  free  for  attach- 
ment. 

In  exactly  a  similar  manner  as  regards  attachment,  direc- 
tion of  winding,  etc.,  must  the  second  limb  be  wound.  The 
only  difference  that  need  be  made  is  that,  for  convenience  of 
having  both  ends  of  wire  at  the  same  end  of  the  dynamo,  it 
will  be  well  to  fasten  the  beginning  of  the  wire  (the  helix)  to 
the  inside  of  the  leg  instead  of  to  the  outside.  Fig.  31,  f, 
will  make  this  clear. 

§  36.  Both  for  the  sake  of  appearance  and  to  further  pro- 
tect the  insulation  from  damp  air,  etc. ,  it  is  advisable  to  give 
the  wires  on  the  limbs  of  the  field-magnets  a  coat  of 
good  varnish.  The  best  for  this  purpose  is  made  by  mix- 
ing about  2  ounces  of  the  best  red  lead  with  yz  an  ounce 
of  good  white  hard  varnish.  The  two  should  be  well  incor- 
porated together  by  working  with  the  brush  intended  to  be 
used  for  laying  on  the  varnish. 

The  varnish  should  be  applied  in  a  thin  layer  with  a  soft 
brush,  so  as  to  disturb  the  paraffine  coating  as  little  as  possible, 
since  if  the  paraffine  mixes  with  the  varnish,  this  latter  never 
dries,  but  remains  a  sticky  mess.  For  this  reason  the  coating 
of  varnish  should  be  allowed  to  dry  without  the  application 
of  heat,  which,  if  the  "  white  hard  "  be  good,  it  will  do  in 
about  eight  to  twelve  hours.  A  second  coat  may  be  given  if 
desired;  but  as  this  generally  fills  up  the  interstices  between 
the  layers  of  wire,  it  detracts  somewhat  from  the  neatness  of 
the  appearance. 

$  37.  The  varnish  being  quite  dry^  the  dynamo  may  again 
be  put  together,  care  being  taken  that  the  parts  are  ad- 
justed in  the  position  which  they  occupied  after  fitting.  If 
this  has  been  properly  done,  the  armature  ought  to  turn 
freely  in  its  bearings  quite  close  to  the  limbs  of  the  field-mag- 
nets, but  without  catching  anywhere. 

Supposing  this  to  be  all  right  (and  it  must  be  so,  or  the 
dynamo  cannot  work  properly),  the  dynamo  must  be  screwed 
down  to  a  baseboard,  wnich  should  consist  of  a  slab  of  oak, 
walnut,  or  mahogany,  10  inches  long  by  8  inches  wide,  and 
at  least  i  inch  thick.  The  two  holes  in  the  lower  flange  in 
the  limb  of  the  field- magnets,  near  the  channel  in  which  the 
armature  revclves,  are  expressly  for  the  purpose  of  clamping 


525 

the  dynamo  to  its  baseboard.  The  baseboard  should  be 
chosen  of  a  well-seasoned  nature — polished,  for  appearance 
sake;  and  the  dynamo  should  be  screwed  to  it  centrally,  with 
the  narrowest  portion  of  the  dynamo  parallel  with  the  narrow- 
est portion  of  the  baseboard. 

ATTACHMENT  OF  THE  WIRES. 

§  38.  The  dynamo  having  been  wound  as  described  (and 
care  must  be  taken  to  have  fulfilled  the  instructions  exactly, 
or  else  the  resulting  magnet  will 
have  two  north  poles,  ortwoj0///>fc 
poles,  instead  of  one  north  and 
one  south),  we  can  proceed  to 
couple  up  the  various  parts.  To 
this  end  we  begin  by  joining  the 
wires  at  the  two  extremities  at 
which  we  left  off  winding.  This 
may  be  effected  by  removing  a 
portion  of  the  covering  of  the 
•wires  (by  scraping  with  a  sharp 
knife)  for  about  an  inch  along  the 
places  where  the  two  wires  cross 
each  other  if  made  to  touch.  (See 
Fig.  320.) 

The  wire  must  be  made  quite 

bright  and  clean  by  rubbing  with  a  bit  of  sandpaper  at  this 
point,  and  then  the  wires  are  twisted  tightly  together  by  the. 
aid  of  a  pair  of  pincers.  A  drop  of  solder,  taken  ujfon  a  hot 
soldering-iron  and  run  along  the  twisted  portion  will  insure 
the  contact  remaining  good.  The  excess  of  wire  should  now 
be  cut  off  from  the  twisted  end  with  a  pair  of  cutting  pliers; 
the  bared  twist  bound  round  with  a  layer  of  darning-cotton, 
varnished  with  the  red  varnish  (§  36),  and  turned  in  out  of  the 
way  between  the  limbs  of  the  magnet.  (Fig.  32,  b.}  k 

We  may  nowproceed  to  magnetize  the  field- magnets. '  For 
this  purpose  we  need  only  attach  the  poles  of  a  single-cell  bichro- 
mate battery,  exposing  from  8  to  10  square  inches  of  negative 
surface,  to  the  wires  of  the  dynamo  for  a  few  seconds;  but  in  or* 
der  to  obtain  results  which  may  be  deducible  from  reason,  and 
which  can  be  corrected  if  mistakes  are  made,  it  is  desirable  to 
determine  beforehand  which  shall  be  the  north  pole  of  our 
future  magnet.  It  will  be  remembered  (§  8)  that  we  have  it 
in  our  power  to  produce  a  north  pole,  to  our  left,  in  a  mass- 


526 

of  iron,  by  passing  a  current  of  electricity  away  from  us, 
ever  it;  and  if  we  wish  to  produce  a  north  pole  to  the  right, 
-the  current  must  come  toward  us,  over  the  mass.  ^ 

Let  us  decide  to  make  a  north  pole  of  the  limb  on  which 
we  began  to  wind  the  wire  on  the  outside.  (See  Fig.  31,  c.) 
To  do  this  the  current  ought  evidently  to  flow  from  the 
limb  of  the  magnet  to  the  observer;  in  other  words,  this  wire 
must  be  attached  to  the  negative  pole  of  the  cell.  (The 
negative  pole  of  the  bichromate  cell  is  the  wire  proceeding 
from  the  zinc,  the  one  attached  to  the  graphite  being  posi- 
tive.) The  positive  pole  of  the  cell  must  be  coupled  to  the 
other  wire,  that  is,  the  one  which  was  started  from  the 
inside  in  winding.  (See  Fig.  31,  f.) 

While  the  battery  is  thus  coupled  up  to  the  dynamo,  we 
can  test  if  we  have  produced  the  effect  desired  by  bring- 
ing a  suspended  magnetized  needle  near  the  supposed  north 
pole  of  the  dynamo.  If  all  has  been  properly  performed,  it 
will  be  found  to  attract  the  south  pole  of  the  poised  needle, 
And  repel  its  north  pole, 

A  few  seconds'  connection  with  the  battery  will  impart 
as  much  magnetism  to  the  field-magnet  as  it  will  retain;  but 
that  little  will  be  sufficient  for  our  purpose.  Our  next  step 
is  to  discover  in  which  direction  the  current  flows  in  our 
armature,  when  we  rotate  the  fly-wheel  in  the  usual  way 
with  the  right  hand  (in  the  direction  of  the  motion  of  the 
hands  of  a  clock).  Before  we  can  do  this  we  must  fasten 
two  "brushes"  or  collectors  on  the  brush-blocks,  in  order  to 
collect  the  electricity  generated  by  the  revolution  of  the 
armature. 

THE  BRUSHES. 

§.39.  These  consist  of  two  pieces  of  springy  sheet  brass, 
y.,  of  an  inch  thick,  3  ^  inches  long,  and  about  ft  of  an  inch 
wide.  They  must  be  bent  twice  at  right  angles,  so  as  to  fit 
tightly  on  to  the  brush-blocks  (§  28,  Fig.  26),  and  slightly 
curved  inward  at  the  longer  portions  so  as  to  press 
with  some  force  against  the  commutator.  (See  Fig. 
32,  c.)  To  fasten  these  on  to  the  blocks,  a  lateral  slot  is  cut 
about  half-way  into  each  brush,  at  about  y$  of  an 
inch  from  the  longest  portion,  of  such  a  width  as  to 
admit  the  shank  of  a  small  screw  passing  into  it.  The  por- 
tion of  the  brush  which  rests  against  the  armature  should  be 
sli;  into  two  or  three  divisions,  and  curved  slightly  upward 
to  avoid  scratching  the  armature. 


527 

These  two  brushes,  though  alike  in  shape,  must  be  pat  in 
opposite  positions  on  the  dynamo ;  that  is  to  say,  the  one 
which  goes  o.n  the  block  to  the  right  of  the  observer  has  the 
longer  portion  above  the  block,  while  the  one  which  goes  on 
the  left-hand  block  has  the  longer  portion  below  the  block. 
Thus  the  commutator  is  rubbed  by  these  two  brushes 
at  diametrically  opposite  points.  Care  must  be  taken  that 
the  two  screws  which  serve  to  fasten  the  brushes  to  the  blocks 
do  not  touch  the  metal  of  the  bolts  which  clamp  the  bear- 
ings to  the  dynamo,  for  if  they  did  the  current  woul  d  short- 
circuit,  and  the  machine  would  not  work.  It  will  also  be  nec- 
essary to  observe  that  sufficient  curvature  be  given  to  the 
longer  portion  of  the  brushes  to  clear  the  bearings  alto- 
gether, otherwise,  of  course,  the 
current  would  pass  into  the  bear- 
ings and  be  short-circuited.  Fig. 
33  shows  the  brushes  in  their 
proper  position ;  a,  a  being  the 
commutator  (exaggerated  in  size 
omewhat  to  show  its  position), 
d,  b  the  brush-blocks,  c,  c  the 
brushes,  and  d,  d  the  screws  which,  by  being  tightened  or 
loosened,  can  increase  or  decrease  the  pressure  of  the  springs  on 
the  commutator,  and  to  which  the  two  wires  which  form  the 
electrodes  of  the  commutator  are  to  be  attached.  These  two 
wires,  which  in  our  machine  may  be  about  3  inches  long,  with 
a  loop  at  each  end,  as  shown  at  Fig.  34  «,  should  be  of  No. 
16  cotton-covered  copper  wire,  the  covering  being  removed 
from  the  two  loops,  which  must  be  made 
quite  bright.  Before  putting  in  the  screws  ^ 

d,  d,  Fig.  33,  each  one  should  be  passed  <j>  ^    ^^    ^ 

into  one  eye  of  one  of  {he  said  wires,  then 
screwed  partly  into  the  brush-block,  when  the  brush  itself 
may  be  pushed  into  its  place  over  the  block,  and  under  the 
screw,    the   slot  in  the  side  admitting  of  this; 
lastly,  the  screw  is  tightened  up  until  the  desired 
pressure  on  the  commutator  is  obtained. 

Fig.  34  shows  the  position  of  the  wire,  screw, 
and  left-hand  brush  on  the  left-hand  block.  The 
1  two  free  ends  of  the  wires  just  described  project 
straight  forward  to  the  front  of  the  machine; 
they  may  be  screwed  down  on  the  baseboard, 
at  the  distance  of  about  3  inches  apart,  by  means 


5-3 

of  a  small  pair  of  binding-screws  ;  the  long  screws  01  which 
are  passed  through  the  free  eyes. 

Y\  e  can  now  test  the  direction  of  the  current  in  our  arma- 
ture. To  do  this  we  place  the  fly-wheel  on  its  bracket,  put 
a  leather  band  (such  as  is  used  for  treadle  sewing-machines) 
round  the  fly-wheel  and  driving  pulley,  then  by  means  of 
two  thin  wires,  which  \ve  will  screw  into  the  hous  of  the 
binding-screws  just  arranged,  we  couple  up  the  brushes  to 
our  galvanometer  ($  3),  and  rotate  the  handle  of  the  fly- 
wheel gently,  in  the  direction  we  intend  to  work  the  machine 
for  the  future. 

A  deflection  of  the  north  pole  of  the  needle,  either  to  right 
or  left,  shows  us  in  which  direction  the  current  is  traveling  ; 
we  carefully  note,  and  mark  with  a  paper  label,  which  is  the 
binding-screw  which  is  sending  the  positive  current  (which  if 
coupled  to  the  wire  over  the  needle,  causes  the  north  pole  to 
turn  to  the  left),  since  this  is  the  binding-screw  which  must 
substitute  the  positive  pole  of  the  battery,  and  to  which  we 
must  attach  the  wire  which  comes  from  the  S  limb  of  our 
dynamo. 

§  40.  Two  binding-screws  are  now  to  be  inserted  into  the 
baseboard,  to  which  the  wires  proceeding 
from  the  limbs  of  the  field-magnet  must  be 
clamped.  These  should  be  placed  about 
i  l/z  inches  from  he  side  of  each  limb,  the 
wires  proceeding  therefrom  being  denuded 
of  their  covering  and  sandpapered  at  the 
extremities  where  they  are  clamped  to  the 
binding-screws.  These  binding-screws  (as 
also  those  connected  with  the  brushes) 
should,  for  the  convenience  of  being  able  to 
couple  up  at  one  and  the  same  time  two  or 
more  wires,  be  of  the  pattern  shown  at  Fig. 
35,  in  which  case  the  extremities  of  the 
field-magnets  may  be  also  formed  into  rings, 
as  sho\vn  at  Fig.  34(7,  and  either  clamped 
down  to  the  baseboard  by  passing  the  long 
screw  c  (Fig.  34)  into  the  ring,  or  the  nut 
p.  a  having  been  removed  for  the  time  being, 

*  ^9*  the  ring  may    be  slipped  over  the  screw  b, 

&  and  then  clamped  by  the  nut  a.  & 

Cor.nection  is  now  to  be  made  between  the  binding-screw 
attached  to"  the  current-sending  or  positive  brush  (the  one 


529 

which  we  have  marked  with  a  paper  label),  and  the  binding- 
screw  coupled  to  the  wire,  starting  from  the  inside  of  the 
limb  of  the  field-magnet  (see  Fig.  31,  c]  by  means  of  a  short 
length  of  No.  16  copper  wire,  well  cleaned,  bent  into  rings  at 
the  ends,  and  clamped  down  as  advised  above. 

If  all  the  instructions  have  been  carefully  carried  out, 
more  especially  those  contained  in  the  last  six  paragraphs, 
we  shall  find  that  on  rotating  the  flywheel  a  powerful  current 
will  flow  between  the  two  remaining  binding-screws — viz., 
the  one  connected  with  the  outside  wire  of  the  field-magnets, 
and  the  other  with  the  negative  brush  of  the  commutator  £ 
current  which  will  be  sufficient  to  heat  to  bright  redness  q.% 
inches  to  5  inches  of  No.  42  platinum  wire,  or  to  light  lour 
5-candle  power  lamps,  arranged  in  parallel  arc. 

The  current  actually  flowing 
through  the  circuit  (the  number  of 
amperes)  will  naturally  depend 
largely  on  the  resistance  interposed 
between  the  poles — that  is  to  say, 
between  the  binding-screws/  con- 
nected with  the  outside  wire  of  the 
field-magnet,  and  the  negative  brush 
of  the  commutators  respectively; 
and  since  the  magnetism  of  the 
field-magnet  depends  entirely  on  the 
amount  of  current  flowing  around 
it,  and  this  again  influences  the  cur- 
rent set  up  in  the  armature,  it  is 
evident  that  every  variation  in  the 
resistance  or  the  interpolar  or  out- 
side circuit  will  produce  a  corres- 
ponding variation  in  the  current,  if 
the  dynamo  be  connected  up  as 
above  described;  and  that  a  very 
much  larger  current  will  traverse  the 
circuit  when  the  resistance  is  small  than  when  the  resistance 
is  great.  When  the  machine  is  doing  its  best  work — that  is 
to  say,  when  the  resistance  of  the  interpolar  is  equal  to  the 
internal  resistance  of  the  machine — the  current  is  equal  to 
that  of  eight  or  ten  Bunsen's  cells  against  an  equal  resist- 
ance. *  Sometimes  it  is  necessary  to  send  the  current  through 
a  greater  resistance;  in  this  case,  in  order  not  to  weaken  too 
greatly  the  magnetism  of  the  field-magnet  by  diminishing  so 


530 

greatly  the  current,  it  is  necessary  to  shunt  off  a  portion  of 
the  current,  and  send  it  round  the  limbs  of  the  field-magnet 
by  another  circuit,  which  diminishes  the  total  resistance. 

To  render  this  clearer,  let  us  suppose  that  we  wish  to  light 
up  four  five-candle  lamps,  having  each  an  approximate  resist- 
ance of  eight  ohms,  and  requiring  a  current  of  about  one 
ampere  each  to  cause  them  to  give  out  their  proper  light.  If 
we  arrange  them  in  series,  as  in  Fig.  36,  #,  when  the  total  re- 
sistance is  the  sum  of  their  separate  resistances  =  thirty-two 
ohms,  then,  as  the  electromotive  force  of  our  machine  when 
at  best  is  about  ten  \olts,  so  ^  represents  the  current  flow- 
ing through  the  lamps,  supposing  even  that  the  dynamo  lost 
no  power  by  the  diminution  of  current  (which  it  does  to  a 
very  great  evcent),  arid  this  current  is  not  sufficient  to  light 
the  lamps.  Hut  if  we  arrange  the  lamps  in  parallel  arc,  as  at 
Fig,  36,  />,  then  the  total  resistance  falls  to  a  quarter  of  one 
single  lamp — that  is  to  say;  it  is 
equal  to  two  ohms  only;  hence  the 
currrent  now  flowing  becomes 
£fl  =  5  amperes,  and  this  divided 
among  the  four  lamps  gives  l*^ 
amperes  each,  which  is  ample. 

Again,  we  find  that  coupling  up 
one  single  lamp  to  the  dynamo 
presents  too  great  a  resistance,  so 
that  no  light  is  given  off,  since  not 
sufficient  current  can  pass  round 
the  field-magnets  to  give  an  elec- 
tromotive force  of  ten  volts.  But 
if  we  insert  a  "  shunt,"  consisting 
of  about  a  dozen  inches  of  No.  30 
iron  wire  between  the  two  binding- 
screws  aforesaid,  as  shown  at  Pig. 
37,  and  then  connect  the  lamp  also 
to  the  said  screws  or  terminals, 
more  current  circulates  round  the 
field-magnets,  since  two  roads  are 
now  open  to  the  current,  the  field- 
magnet  becomes  more  powerfully 
magnetic,  and  in  its  turn  induces 
a  much  more  powerful  current  in 
the  armature,  and  so  on  until 
current  enough  is  produced  to 


531 

light  up  the  lamp.  The  resistance  of  the  "shunt"  to  be 
inserted  between  the  terminals,  to  produce  the  best  result, 
will  depend  on  the  resistance  of  the  interpolar.  If  this 
latter  be  low,  no  "  shunt  "  (or  one  of  very  great  resistance) 
will  be  required;  but  if  the  resistance  of  the  interpolar  be 
very  high,  the  resistance  of  the  "  shunt "  must  be  corre- 
spondingly low,  or  else  not  enough  current  will  pass  to 
magnetize  the  field-magnet,  and  the  dynamo  will  give  no 
current. 

Fig.  38  represents  the  dynamo  complete. 

The  machinist,  mechanic,  engineer,  artisan,  student  or 
schoolboy  who  has  not  only  carefully  read  the  preceding 
pages  on  the  dynamo,  but  has  made,  or  attempted  to  make, 
a  machine  by  closely  following  the  instructions,  will  have  ac- 
quired a  knowledge  of  the  rudiments  of  electrical  science 
which  will  enable  him  to  explore  still  further  into  this  fasci- 
natrhg  branch  of  the  mechanical  arts.  This  book  is  merely 
designed  to  start  the  explorer  on  his  interesting  journey; 
new  discoveries,  new  inventions,  and  new  surprises  are  daily 
events  in  the  electrical  world;  but,  the  fundamental  prin- 
ciples, the  foundation  laws,  never  change,  and,  wHh  a  fair 
understanding  of  the  underlying  structure,  the  growing  fabric 
can  be  watched  with  satisfactory  understanding. 

The  wide-awake  mechanic  will  endeavor  to  keep  abreast 
with  the  times.  He  will  be  quick  to  note  any  novel  dis- 
covery, any  important  innovation,  and  in  no  branch  of  his 
art  are  the  possibilities  of  world-thrillinp-  sensations  greater 
than  in  the  electrical  field. 

Suppose,  then,  that  you  have  made  a  dynamo,  such  as 
described  in  this  article ;  suppose  that  you  have  it  in  active 
operation,  and  it  is  giving  you  a  current  equal  to  eight  or  ten 
Bunsen's  cells ;  you  have  an  instrument  which  will  be  of  the 
highest  value  to  you  in  your  future  researches ;  instead  of 
finding  the  study  a  laborious  grind,  a  dry,  musty,  brain 
killer,  you  will  find  yourself  fascinated  with  the  opening 
pages  of  the  mysterious  book  when  it  is  read  by  the  light  of 
the  electrical  current  generated  by  the  dynamo  made  by  the 
skill  of  your  own  hands. 

Too  much  value  cannot  be  given  a  knowledge  of  the  science 
of  electricity  and  its  application  to  the  mechanical  arts,  in- 
creasing every  day,  will  bring  it  in  contact  with  every 
mechanic  and  artisan  in  the  country.  Make  a  dynamo  as 
described,  study  as  you  make,  and  you  will  be  able  to  keep 
abreast  of  the  times. 


532 
MANAGEMENT  OF  DYNAMOS. 

The  use  of  dynamos  is  becoming  so  general  for  electric 
lighting  and  power  that  the  following  hints  on  the  manage- 
ment and  care  of  dynamos  may  be  of  use  to  engineers,  es- 
pecially as  the  care  of  the  dynamo  is  usually  placed  in  the 
hands  of  the  engineer,  and  the  machine  placed  in  the  engine- 
room. 

Before  the  dynamo  is  started  for  its  day's  run  all  the  lubri- 
cators should  be  rilled  up.  For  this  purpose  none  but  cop- 
per oil-cans  should  be  used. 

Next  in  order,  the  brushes  should  receive  attention,  and 
should  be  carefully  examined  to  see  that  they  are  properly 
trimmed  and  thoroughly  well  screwed  up  to  their  holders. 

If  the  brushes  touch  at  a  bevel  angle,  they  should  be  oc- 
casionally trimmed  with  a  file,  so  that  they  will  preserve  an 
even  bearing  upon  the  commutator.  To  do  this  properly  the 
brushes  should  be  removed  from  the  machine. 

Never  leave  files  or  iron  tools  near  the  dynamo.  If  the 
machine  is  in  a  shop  where  iron  filings  are  flying  about  it 
should  be  examined  frequently  to  see  if  any  filings  have  been 
attracted,  and  if  any  are  found  they  should  be  removed. 
It  is  always  best,  if  the  dynamo  is  of  necessity  placed  in 
such  a  position,  that  it  should  be  boxed  in  as  completely  as 
possible. 

After  the  machine  has  been  started  the  brushes  should  be 
put  down;  when  the  run  is  over  the  brushes  should  be  raised 
before  the  engine  is  stopped. 

The  commutator  must  be  kept  clean  and  bright  and  free 
from  metallic  dust  of  any  kind.  It  should  be  occasionally 
wiped  with  a  clean  rag  (never  use  waste),  very  slightly 
smeared  with  oil  or  vaseline;  should  the  brushes  press  too 
heavily  it  will  be  worn  into  ruts,  should  they  not  press 
firmly  enough  its  segments  will  v/ear  unequally  along  their 
edges. 

As  soon  as  the  dynamo  is  started  the  brushes  should  be 
carefully  so  rocked  that  they  touch  at  the  neutral  points;  if 
this  position  is  not  carefully  observed  the  sparking  may 
rapidly  ruin  the  commutator. 


533 


ELECTRICITY  SIMPLIFIED. 

No  one  knows  what  electricity  really  is.  It  seems,  how- 
ever, to  be  present  everywhere.  In  the  air,  in  the  earth,  in 
the  water,  in  trees,  animals,  man,  fishes,  metais,  everywhere, 
but  no  one  can  tell  what  it  is,  We  know  what  steam  is,  for 
we  can  divide  it  into  its  various  parts.  We  know  what  a  gas 
is,  for  we  can  smell  it,  or  taste  it,  or  weigh  it  We 
know  what  the  air  is;  but  we  cannot  see  electricity,  it  has  no 
taste,  it  has  no  weight,  no  substance,  but  it  is  called  a  force, 
which  is  made  known  to  us  by  the  peculiar  fact  that  it  willat- 
tract  or  repel. 

For  instance,  if  you  take  a  piece  of  glass  —  a  small  glass 
rod  or  tube,  and  a  piece  of  sealing-wax,  and  bring  them  near 
some  small  scraps  of  paper,  or  shreds  of  cotton,  a  feather,  or 
gold  leaf,  or  bran,  you  will  not  notice  anything  particular. 
There  will  be  no  movement  of  any  kind.  But,  suppose  you 
rub  the  glass  and  the  sealing-wax  briskly  with  a  piece  of  dry 
woolen  cloth,  then  bring  them  near  the  light  substances  men- 
tioned, you  will  find  that  the  paper,  or  cotton,  or  gold  leaf, 
or  bran,  or  feathers,  will  spring  or  jump  toward  the  glass  rod 
or  sealing-wax,  even  if  quite  a  little  distance  is  between  them, 
and  will  cling  to  the  glass  and  wax. 

You  will  further  notice,  that,  after  a  time,  the  paper,  etc., 
will  jump  away  (not  simply/^//)  from  the  glass,  or  wax,  as  if 
they  had  been  snapped  off. 

Thus,  there   was  something   happened  when  the  glass  or 
\vax  was  rubbed  by  the  woolen  cloth,  something  which  gave 
the  glass  or  wax  the  property  of  attracting  the  paper,  etc. 
and  afterward  of  repelling  or  casting  off  the  same  paper,  etc. 

This  something  was  the  electricity  excited  by  the  friction 
between  the  glass  or  wax  and  the  woolen  cloth. 

The  writer  of  this  article  is  smoking  an  ordinary  pipe, 
which  has  an  amber  mouth  piece.  He  first  wiped  the  moist- 
ure from  the  amber,  and  then  rubbed  it  for  a  few  seconds 
upon  the  green  cloth  of  his  desk,  and,  bringing  it  near  some 
little  bits  of  paper,  he  found  that  the  paper  sprang  and 
remained  upon  the  amber,  ai?d,  not  only  that,  but  the  bit  of 
paper  next  to  the  amber  attracted  another  bit  of  paper,  and 
that  second  piece  another,  until  three  little  bits  of  paper,  like 
a  chain,  were  hanging  from  the  amber. 

First,  the  amber  was  electrified,  then  each  bit  of  paper,  as 


534 

it  came  in  contact  with  the  electrified  amber,  became  electri- 
fied, and  attractec  another  bit  to  itself.  Now,  there  are  two 
kinds  of  electricity,  positive  and  negative.  The  positive  at- 
tracts and  the  negative  repels.  This  last  statement  can  be 
easily  proved.  Make  two  little  balls  from  the  pith  of  the 
elder  bush,  or  any  other  plant  that  has  a  dry,  light  pith. 
When  quite  dry,  fasten  a  fine  silk  thread  to  each  pith  ball, 
and  suspend  them  from  some  convenient  point  so  they  will 
swing  freely. 

Electrify  the  sealing-wax  with  the  woolen  cloth,  but,  elec- 
trify the  glass  rod  with  a  piece  of  soft  silk.  Touch  one  pith 
ball  with  the  wax,  and  it  will  follow  it  for  a  moment  and  then 
shoot  away,  just  as  the  paper  did.  At  the  same  time  touch 
the  other  pith  ball  with  the  glass  and  it  will  do  the  same 
thing.  If  you  bring  the  wax  and  glass  nearer  the  pith  balls 
after  they  have  been  repelled,  you  will  notice  that  they  will 
keep  away  from  them.  Now  quickly  change  the  wax  and 
glass,  so  that  they  will  touch  the  pith  ball  that  was  first  at- 
tracted and  then  repelled  by  the  glass,  and  you  will  see  that  < 
the  wax  will  attract  it,  and,  if  you  touch  the  other  pith  ball 
with  the  glass,  it  will  be  attracted  also. 

If  you  have  taken  the  trouble  to  try  this  simple  experi- 
ment, you  have  learned  that  there  is  a  positive  electricity,  or 
the  electricity  that  attracts,  and  a  negative  electricity,  or  the 
electricity  that  repels. 

You  have  also  learned  that  the  ball  which  was  repelled  by 
the  glass  was  attracted  by  the  sealing-wax,  and  the  ball  that 
was  repelled  by  the  sealing-wax,  was  attracted  by  the  glass. 
This  proves  that  the  electricity  developed  on  glass  is  differ- 
ent in  kind  from  that  developed  on  sealing-wax,  and  by  re- 
peating the  experiment  with  other  substances,  it  will  be  found 
that  all  electrified  bodies  act  like  either  the  glass  or  the  sealing- 
wax. 

There  is  another  thing,  two  bodies  charged  with  (or  hav- 
ing) positive  electricity  will  repel  each  other,  and  the  same 
thing  will  happen  if  the  two  bodies  are  charged  with  negative 
electricity,  but,  if  one  is  charged  with  positive,  and  the  other 
with  negative  electricity,  they  will  be  attracted  t©  each  other. 

The  electricity  which  is  excited  by  rubbing  two  substances 
together  is  c&lle&frictional  electricity. 

It  has  been  shown  by  the  above  experiments  that  an  elec- 
trified substance  can  impart  electricity  to  another.  This  is 
called  conduction.  It  is  not  necessary  that  the  bodies  should 


535 

touch.  They  may  be  connecter5  by  a  copper  wire  or  a  flax 
thread.  But,  if  connected  by  a  silk  thread,  or  a  piece  of  rub- 
ber, the  electrified  body  will  not  electrify  the  other.  Some 
substances  transmit  electricity  readily  and  others  do  not, 

Those  that  offer  little  resistance  to  the  passage  of  electricity 
are  called  conductors;  those  that  offer  great  resistance  are 
called  non-conductors  or  insulators.  Conductors  which  are 
held  up,  or  wrapped  in  non-conductors  are  said  to  be  insu- 
lated. Silver,  copper  and  iron  are  conductors.  Rubber, 
gutta-percha,  glass,  porcelain  and  silk  are  non-conductors  or 
insulators.  A  copper  wire,  if  wrapped  in  silk  or  rubber, 
would  be  insulated. 

For  practical  work,  conductors  are  made  of  wire,  either 
copper  or  iron,  usually  having  a  covering  made  of  woven  silk 
or  cotton. 

Frictional  electricity  is  generated,  for  purposes  where  a 
large  quantity  is  needed,  by  electric  machines,  which  con- 
sists of  a  circular  glass  plate  from  one  to  four  feet  in  diam- 
eter, that  is  turned  by  a  crank.  Against  the  sides  of  this  plate 
are  cushions  made  of  silk  or  leather,  coated  with  mercury. 
On  turning  the  crank,  the  glass  plate  revolves  between  the 
silk  cushions  and  is  electrified.  The  electricity  is  gathered  or 
caught  by  metal  points  called  combs,  and  is  carried  off  by 
conductors. 

Electricity  is  also  developed  by  chemical  action.  AH  chem- 
ical changes  produce  electric  action.  This  is  true  whether  the 
substance  is  a  solid,  liquid  or  gas,  but  the  chemical  action 
between  liquids  and  metals  gives  the  most  satisfactory  result. 
Electricity  thus  developed  is  called  the  Voltaic  or  Galvanic 
electricity.  As  was  said  before,  we  do  not  know  just  what 
electricity  is,  but  we  do  know  that  by  combining  certain 
liquids  and  metals,  or  by  making  certain  chemical  combina- 
tions, we  can  make  all  the  electricity  we  want. 

If  we  take  a  strip  of  copper  and  one  of  zinc,  and  place 
them  in  a  glass  jar  which  contains  some  dilute  sulphuric  acid 
(that  is,  water  which  has  had  sulphuric  acid  put  in  it),  keep- 
ing the  zinc  and  copper  separated,  but  connecting  them  above 
the  glass  jar  by  a  wire  conductor,  we  will  have  a  current  of 
electricity  produced.  In  fact,  two  currents,  opposite  in  kind 
and  direction,  are  produced— but,  remember  that,  whenever 
the  direction  of  the  electric  current  is  referred  to,  it  means 
the  direction  of  \he  positive  current. 

It  is  necessary,  for  the  production  of  an  electric  current :n 


536 

this  way, that  the  liquid  should  have  a  greater  action  upon 
one  metal  than  upon  the  other.  The  metal  which  is  most 
vigorously  acted  upon  by  the  acid  is  called  the  positive 
plate  (it  generates  jQr&  might  say, the  electricity),  the  other 
is  the  negative  plate  (it  collects  the  electricity).  So  the  cur- 
rent starts  from  the  positive  plate,  through  the  liquid  to 
the  negative  plate,  then  out  of  the  glass  jar  through  the 
wire  joined  to  the  negative  plate,  and  back  through  the 
other  wire  to  the  positive  plate.  In  the  apparatus  de- 
scribed above(called  a  galvanic  or  voltaic  element  or  cell) 
the  zinc  is  ^& positive  plate,  copper  the  negative  plate. 

The  wires  attached  to  the  copper  and  zinc  are  called 
electrodes  or  poles.  The  electrode  attached  to  the  copper 
plate  (which  is  the  negative)  is  called  the  positive^  elec- 
trode. The  one  attached  to  the  zinc  plate  (which  is  the 
positive  plate),  is  called  the  negative  electrode. 

When  two  or  more  voltaic  or  galvanic  elements(or  cells) 
are  connected  together, the  apparatus  is  called  a  galbanic 
or  voltaic  battery.  In  a  battery  the  positive  plate  of  one 
cell  is  connected  to  the  negative  plate  of  the  next  cell, and 
so  on.  When  this  is  done,  they  are  said  to  be  coupled  in 
series.  Sometimes  all  of  the  positive  plates  are  connected 
by  wire,  and  all  of  the  negative  plates  by  another  wire. 
The  cells  are  then  said  to  be  joined  in  ' '  multiple  arc. ' ' 

Batteries  for  producing  electricity  are  divided  into  two 
classes,  called  ' 'open  circuit"  batteries,  and  "closed  cir- 
cuit' '  batteries.  The  open  circuit  batteries  are  used  when 
the  electricity  is  not  required  constantly,  but  is  used  for  a 
short  time  at  different  periods.  Such  batteries  are  used 
with  telephones,  electric  bells,  hotel  annunciators,  etc. 

Closed  batteries  are  used  where  the  work  is  continu- 
ous, as  for  electric  lights,  motors,  etc. 

(As  galvanic  cells  can  be  readily  purchased,  and  are  not 
expensive,  it  is  recommended  that  a  cell  for  open  circuit 
and  one  for  closed  circuit  be  purchased.  For  open  circuit 
buy  one  of  the  following  makes:  Leclanche  cell,  or  the 
Law;  for  closed  circuit,  the  Grenet.  These  cells  can  now 
be  bought  of  any  electric  supply  store). 

Batteries  as  described,  generating  or  producing  elec. 
tricity  by  the  action  and  combination  of  chemicals 
liquids  and  metals,  are  called  "Primary  Batteries" 

There  is  another  style  of  batteries, called  Secondary  or 
Storage  batteries.  A  secondary  battery  does  not  of  itself 


537 

make  an  electric  current,  but  is  used  to  store  up  and  hold  the 
energy  of  an  electric  current,  which  is  led  to  it  from  a 
primary  battery  or  a  dynamo.  The  electrical  energy  can 
then  be  kept  until  it  is  wanted  for  use. 

A  secondary  or  storage  battery  usually  consists  of  a  glass 
jar,  holding  plates,  made  of  lead,  and  some  water,  which  is 
made  slightly  acku  There  are  always  two  lead  plates  in  a 
secondary  battery,  but  there  may  be  any  number  above  that, 
and  these  plates  are  called  electrodes.  Upon  the  positive 
electrode  is  spread  a  paste  made  of  red  lead.  Upon  the  neg- 
ative electrode  is  spread  a  paste  made  of  litharge. 

When  the  plates  are  thus  prepared,  they  are  put  into  the 
acidulated  water  (which  is  held  by  the  glass. jar),  and  a  wire 
from  each  plate  is  connected  with  conductors  from  a  dynamo 
or  a  primary  battery.  When  all  is  ready  for  charging,  the 
current  is  turned  on,  and  enters  by  one  plate,  coming  out  by 
the  other. 

The  electric  current,  of  course,  meets  with  some  resistance 
from  the  plate  and  the  paste,  and  this  resistance  causes  it  to 
work  upon  the  paste  in  such  a  manner  that  a  chemical  change 
is  made,  that  is,  the  paste  on  the  positive  electrode  has  been 
changed  to  peroxide  of  lead,  and  that  in  the  negative  electrode 
into  spongy  lead. 

When  the  current  has  passed  from  one  plate  to  another  in 
this  way  for  a  time,  the  wires  are  disconnected  from  the 
dynamo  or  primary  battery. 

As  the  acidulated  water  is  still  left  in  the  glass  jar,  the 
paste  upon  the  plates  begins  to  work  to  get  back  to  its  orig- 
inal shape,  and  it  is  this,  working  that  causes  a  current  of 
electricity,  which  will  light  lamps,  run  a  motor  or  do  anything 
the  current  from  the  dynamo  or  primary  battery  would  do. 

After  the  paste  has  resumed  its  original  form,  the  battery 
is  said  to  be  discharged,  and  can  then  be  again  charged. 

It  is  customary,  in  practical  use  of  secondary  or  storage 
batteries,  to  charge  them  from  a  dynamo.  These  batteries 
are  largely  used  for  street  car  purposes.  A  motor  is  attached 
to  the  axle  of  the  car,  and  is  energized  by  the  storage  bat- 
teries placed  beneath  the  seats,  the  batteries  having  been 
charged  from  a  dynamo  located  at  the  terminus  of  the  road. 

In  the  article  on  "How  to  Build  a  Dynamo,"  commencing 
on  page  478,  the  magnetizing  effects  of  an  electric  current 
are  explicitly  explained. 


Electricity,  although  it  has  no  weight  or  tangible  form,  is 
measured  as  accurately  as  is  steam,  or  air,  or  coal. 

The  three  measurements  most  commonly  used  are 
The  Volt; 
The  Ampere; 
The  Ohm. 

THE  VOLT  is  the  practical  unit  of  measurement  of  press- 
ure. That  is,  "  volt "  bears  the  same  relation  to  electricity 
as  "  pounds  "  does  to  steam.  When  we  speak  of  steam  in 
a  boiler  or  in  the  cylinder  of  a  steam  engine,  we  say:  "  There 
is  a  pressure  of  ten  or  fifty  or  a  hundred  pounds  to  the 
square  inch,"  and  steam  pressure  is  calculated  and  measured 
in  pounds;  thus,  a  "  pound "  is  the  unit  of  pressure  or 
intensity. 

Now,  electricity  moves  with  a  certain  force  and  pressure; 
this  force  is  called  the  electro-motive  force  (represented  by  the 
letters  E.  M.  F»),  and  the  unit  of  pressure  or  intensity  of  this 
force,  is  called  a  volt.  Thus  we  say  that  a  dynamo  has  an 
electro-motive  force  of  117  volts,  or  that  the  intensity  of  a 
galvanic  cell  is  ll/2  volts,  etc. 

Suppose,  instead  of  steam,  we  had  used  the  water  which 
comes  into  the  house  from  the  water-works,  as  an  illustra- 
tion. That  water  comes  in  through  pipes  and  is  forced 
through  these  pipes  by  pumps. 

Now,  the  water  comes  with  a  pressure  of  so  many  pounds 
to  the  inch,  and  "  pound  M  is  the  unit  by  which  this  pressure 
is  measured.  The  water  would  not  flow  through  the  pipes 
unless  it  was  pushed  or  forced  through,  neither  would  elec- 
tricity flow  through  the  wires  without  there  was  pressure 
back  of  it,  and  this  pressure  is  measured  in  volts. 

THE  AMPERE  is  the  practical  unit  of  the  rate  of  flow  of 
electricity.  Electricity  flows  through  the  wire  at  a  certain 
pressure,  just  as  water  flows  through  pipes  at  a  certain 
pressure.  Now,  if  we  wanted  to  speak  of  the  water  coming 
through  the  pipes,  we  would  say  that  the  water  was  flowing 
at  the  rate  tf/five  gallons  per  minute,  and  if  the  pressure  on 
the  water  was  ten  pounds,  we  would  say  that  the  water  was 
flowing  at  the  rate  of  five  gallons  per  minute,  at  a  pressure 
of  ten  pounds  to  the  inch. 

In  speaking  of  the  electric  current,  we  say,  "  that  a  certain 
current  of  electricity  is  flowing  at  the  rate  of  one  ampere^ 
acted  upon  by  an  electro-motive  force  of  90  volts,  or  a 
lamp  requires  a  current  of  two  amperes •,  at  a  pressure  of  100 
volts  to  light  it. 


539 

Thus,  the  volts  of  pressure  forces  the  current  to  flow  through 
the  wires  at  a  certain  rate  per  second,  and  this  rate  is  called 
the  ampere. 

THE  OHM  (pronounced  like  "  ome  "  in  home)  is  the  practi- 
cal unit  of  measurement  of  resistance. 

Electricity  is  conducted  or  carried  from  one  place  to 
another,  for  the  purpose  of  telegraphing,  telephoning,  light, 
power,  etc.,  by  means  of  wires,  made  of  copper  or  iron. 

These  wires  do  not  permit  the  current  to  flow  through 
them  without  hindrance.  There  is  always  a  certain  amount 
of  resistance  to  the  current,  and  the  smaller  the  wire,  the 
more  resistance  there  is.  Sometimes  the  current  is  too  strong 
for  the  wire,  and  it  becomes  hot,  gets  red,  and  burns  up. 

That  is,  the  wire  is  too  small  for  the  volts  pressure,  and 
amperes  of  current  of  electricity,  and  the  current,  trying  to 
get  through,  and  fighting  to  overcome  this  resistance,  becomes 
red  hot  and  then  may  melt. 

This  resistance  is  measured  by  the  ohm;  thus,  a  copper 
wire  of  such  a  size  has  a  resistance  of  so  many  ohms. 


RULES  AND  REGULATIONS. 

FOR 

PROPERLY  WIRING  AND  INSTALLING  ELECTRIC  LIGHT 
PLANTS. 

The  following  rules  and  regulations  for  the  prevention  of 
fire  risks  arising  from  electric  lighting,  were  issued  by  the 
Society  of  Telegraph  Engineers  and  Electricians  of  England, 
and  every  person,  connected  with  an  establishment  using 
electric  lights,  whether  owners  or  employes,  should  care- 
fully read  them,  and  be  governed  thereby  : 

The  chief  difficulties  which  beset  the  electrical  engineer  are 
internal  and  invisible,  and  can  only  be  effectually  guarded 
against  by  testing  with  special  apparatus,  and  electric  cur- 
rents. They  arise  from  leakage  and  bad  connections  and 
joints,  which  lead  to  waste  of  energy  and  the  production  of 
heat  to  a  dangerous  extent. 

MOISTURE  DANGER. — The  necessity  for  guarding  against 
the  presence  of  moisture,  which  leads  to  loss  of  current  and 
to  the  destruction  of  the  conductors  and  apparatus,  by  cor- 
rosion and  otherwise,  cannot  be  too  strongly  urged. 


EARTH  DANGER. — Injudicious  connections  of  any  part  of 
the  circuit  with  the  "  earth"  tend  to  magnify  every  other 
source  of  difficulty  and  danger. 

IGNORANCE  AND  INJUDICIOUS  ECONOMY. — Many  of  the 
dangers  in  the  application  of  electricity  arise  from  ignorance 
and  inexperience  on  the  part  of  those  who  supply  and  fit  up 
inadequate  plants,  and  frequently  from  injudicious  economy 
on  the  part  of  the  user. 

SAFETY  IN  CONSULTING  EXPERIENCED  ENGINEERS. — 
The  greatest  element  of  safety  is,  therefore,  the  employment 
of  skilled  and  experienced  electrical  engineers  to  specify  the 
method  in  which  the  work  is  to  be  done,  and  the  quality  of 
the  materials  to  be  employed,  and  to  supervise  the  execution 
of  the  work. 

CONDUCTORS. 

1.  SECTIONAL  AREA. — Conductors  (wires)    must    have  a 
sectional  area  and  conductivity  so  porportioned  to  the  work 
they  have  to  do,  that,  if.  double  the  current  proposed  is  sent 
through  them,  the  temperature  of  such  conductors  shall  not 
exceed  150°  Fahr. 

2.  ACCESSIBILITY. — The   conductors,  or    their  coverings, 
should  be  placed  in  sight,  if  possible,  and  they  should  always 
be  as  accessible  as  circumstances  will  permit. 

3.  INSULATING. — Within  buildings   they   should  be  insu- 
lated; and  this  rule  applies   equally  to  all  conductors   and 
parts  of  fittings  which  may  have  to  be  handled. 

4.  MAXIMUM  TEMPERATURE. — Whatever  insulating  mate- 
rial is  employed   it    should  not   soften   until  a    temperature 
of  170°  Fahr.,  has  been  reached,  and,  in  all  cases,  the  material 
must  be  damp-proof. 

5.  CASINGS. — When     wires     pass    through    roofs,   floors, 
walls  or  partitions,  and  where  they  cross,  or  are  liable  to  touch 
metallic  substances,  such  as  bell  wires,  iron  girders,  or,  pipes 
they  should  be   thoroughly  protected  by  suitable  additiona' 
covering;  and,   where  they  are  liable  to  abrasion  from  an 


cause,   or  the  depredations  of  rats   or   mice,  they  should  be 
encased  in  some  suitable  hard  material. 

6.  DISTANCE  APART. — Conductors  should  be  kept  as  far 
apart  as  circumstances  will  permit,  the  spacing  between  them 
being  governed  by  their  potential  difference. 

7.  INFLAMMABLE  STRUCTURES. — When   conductors   are 
carried  in  very  inflammable  structures,   precaution  should  be 
taken  to  isolate  them  therefrom. 

8.  METALLIC  ARMOR. — Conductors  which  are  protected 
on  the  outside  by  lead,  or  metallic  armor  of  any  kind,  require 
the  greatest  care  in  fixing,  on  account  of  the  large  conducting 
surface  which  would  become  connected  to  the  core  in  the 
event  of  metallic  contact  between  them. 

9.  JOINTS.—  All  joints  must  be  mechanically  and  electrically 
perfect,  to   prevent  heat   being   generated  at  these  points. 
When  soldering  fluids  are  used  in  making  joints,  the  latter 
should  be   carefully   washed   and  dried  before  insulation  is 
applied. 

10.  GAS   AND    WATER  PIPES. — Under  all  circumstances 
complete  metal  circuits  must  be  employed.     Gas  and  water 
pipes  must  never  form  part  of  a  circuit,  as  their  joints  are 
rarely  electrically  good,   and  therefore  become  a  source  of 
danger. 

11.  OVERHEAD     CONDUCTORS. — Overhead    conductors, 
whether  passing  over  or  attached  to  buildings,  must  be  insu- 
lated at  their  points  of  support. 

Precaution  must  be  taken  to  obviate  all  risks  of  short-cir- 
cuiting, where  they  are  likely  to  touch  a  building,  or  other 
overhead  conductors  and  wires,  either  by  their  own  fall  or 
by  being  fallen  upon  by  other  conductors. 

12.  LIGHTNING   PROTECTOR. — In   the  case   of  overhead 
wires,  every  main  should  have  a  lightning  protector  at  each 
point,  where  it  enters  or  branches  into  a  building. 


542 

13.  INSULATION  RESISTANCE. — The  insulation  of  a  system 
of  distribution  should  be  such,  that  the  greatest  leakage  from 
any  conductor  to  earth  (and,  in  case  of  parallel  working,  from 
one  conductor  to  the  other,  when  all  branches  are  switched 
on,  but  the  lamps,  motors,  etc.,  removed),  does  not  exceed 
one  five  thousandth  part (Q^QQ)  of  the  total  ciirrent  in  tended  for 
the  supply  of  the  said  lamps,  motors,  etc.,  the  test  being 
made  at  the  usual  working  electro-motive  force. 


SWITCHES. 

14.  CONSTRUCTION  AND  ACTION. — Every  switch  or  com- 
mutator should  be  of  such  construction   as  to  comply  with 
the  following  condition,  namely:     That  when  the  handle  is 
moved  or  turned  to  or  from  the  positions  of  "  on  "  and  "  off," 
it  is  impossible  for  it  to  remain  in  any  intermediate  position, 
or  to  permit  of  a  permanent  arc,  or  heating. 

15.  INSULATED  HANDLES.—  The  handles  of  every  switch 
must  be  completely  insulated  from  the  circuit. 

16.  MAIN  SWITCHES,  POSITION  OF. — The  main  switches 
of  a  building  should  be  placed  as  near  as  possible  to  the  point 
of  entrance  of  the  conductors,  or  to  the  generators  of  the  cur- 
rent if  they  are  within  the  building  itself     Switches  should 
be  provided  on  both  leads. 

17.  SWITCH  BOARDS. — Switch  boards  should  bear  clear 
instructions  for  their  use  by  the  inexperienced. 


ELECTRICAL  FITTINGS  GENERALLY. 

18.  BASES. — Switches,  commutators,  resistances,  bare 
connections,  lamps,  etc.,  must  be  mounted  on  incombustible 
bases;  cut-outs,  mounted  on  bases  of  wood,  rendered  unin- 
flammable, are  admissible;  vulcanite  bases  are  undesirable  in 
damp  situations.  The  cracking  of  porcelain  and  earthen- 
ware fittings  is  a  source  of  danger  which  can  be  avoided  by 
precautions  in  fixing. 


CUT-OUTS. 

19.  IMPERATIVE  USE  OF. — All  circuits  should  be  protected 
by  cut-outs ;  and  all  leads  from  the  mains,  or  small  conductors 
from  larger  ones,  must  be  fitted  with  cut-outs  at  their  branch- 
ing points 

20.  SITUATION.— Where  fusible  cut-outs   are  used,  the 
section  should  be  so  situated  within  its  frame  that  the  fused 
metal  cannot  fall  where  it  may  cause  a  "  short  circuit  "  or  an 
ignition. 

21.  FOR  (  +  )  AND  ( — )  MAINS. — For  all  main  conductors 
a   cut-out   should   be   provided   for   both    the   "  flow "    and 
"  return ; "  and  the  two  fusible  sections  must  not  be  in  the 
same  compartment. 

22.  FOR  PORTABLE  FITTINGS. — The  flexible  wires  of  por- 
table fittings  must  in  all  cases  be  protected  by  cut-outs  at 
their  fixed  points  of  connection. 

ARC  LAMPS. 

23.  GLOBES,  ETC. — Arc  lamps  must  always  be  guarded  by 
globes,  netted   or   otherwise,   so    to   prevent  danger    from 
ascending  sparks,   or   from   falling  glass   and   incandescent 
pieces  of  carbon. 

24.  INSULATION  OF  PARTS. — All  parts  of  the  lamps  and 
lanterns  which  are  liable  to  be  handled  (except  by  the  persons 
employed  to  trim  them),  should  be  insulated. 

THE  DYNAMO. 

25.  INSULATION,  SITUATION,  ETC.— The  armatures  and 
field  magnet  coils  should  be  thoroughly  insulated.     Dynamos 
should  always  be  fixed  in  dry  places,  and  they  must  not  be 
exposed  to  dust  flyings   or  other  industrial  waste  products 
carried  in  suspension  in   the  a.r.     They  should  not  be  per- 


544 

mitted  in  the  working  rooms  of  mills,  where  the  liability  to 
such  dangers  exists,  or,  where  any  inflammable  manufactures 
are  carried  on,  or  inflammable  materials  are  stored. 

26.  MOTORS. — Motors  should  be  subject  to  the  same  con- 
ditions; but  when  it  is  necessary  to  use  them  in  positions  such 
as  those  above  referred  to,  they  must  be  securely  cased  in, 
such  cases  having  a  non-combustible  lining. 


BATTERIES. 

27.  INSULATION. — Both  primary  and  secondary  batteries 
should  be  placed  and  used  under  the  same  precautions  as  pre- 
scribed for  dynamos;  and  the  room  in  which  they  are  placed 
should  be  well  ventilated.  The  batteries  themselves  must  be 
well  insulated. 


MAINTENANCE. 


28.  TESTING. — The  value  of  frequently  testing  and  inspect- 
ing the  apparatus  and  circuits  cannot  be  too  strongly  urged  as 
a  precaution  against  fire.  Records  should  be  kept  of  all  tests, 
so  that  any  gradual  deterioration  of  the  system  may  be 
detected. 


tu 


29.  CLEANLINESS. — Cleanliness  of  allaparts  of  the  appara- 
is  and  fittings  is  essential  to  good  maintenance. 

30.  REPAIRS. — No  repairs  or  alterations  must  be   made 
when  the  current  is  "  on." 


GENERAL. 

All  the  above  rules  for  the  reduction  to  a  minimum  of  the 
risks  from  fire,  are  also  applicable  in  principle  to  installations 
of  electricity  for  other  uses  than  that  of  lighting :  they  also 
include  precautions  necessary  to  avoid  risks  of  injury  to  per- 
sons, whether  the  conductors  and  apparatus  are  situated 
inside  or  outside  a  building. 


545 

A  FEW  POINTS  FOR  INVENTORS   REGARDING 
PATENTS. 

The  progressive  mechanic  is  always  an  inventor.  He 
may  not  have  his  invention  patented,  but  he  is  constantly 
planning  ways  and  means  to  improve  the  mechanism 
and  tools  which  he  uses,  or  devising  better  methods  of 
working  and  manufacturing. 

To  those  mechanics  who  deem  their  invention  patent- 
able,  the  following  pointers  will  be  of  value: 

It  is  always  well  to  thoroughly  investigate  the  patent 
office  reports  before  undertaking  the  expense  and  trouble 
incident  to  the  application  and  issue  of  patents. 

In  nearly  every  town,  of  any  size,  bound  volumes  of 
patent  office  reports,  with  the  all-important  index,  may 
be  found  in  the  Public  Library. 

Thoroughly  search  and  examine  these  reports  before 
you  apply  for  a  patent.  It  may  save  you  time  and  money. 

CORRESPONDENCE. — All  business  with  the  patent 
office,  which  is  located  at  Washington,  D.  C.,  should 
be  transacted  in  writing. 

No  attention  is  paid  to  any  oral  instructions  or  petitions 

All  office  letters  must  be  sent  in  the  name  of  the 
"  Commissioner  of  Patents. ' ' 

All  express,  freight  and  postage  charges  must  be  fully 
prepaid. 

A  separate  letter  should  in  every  case  be  written  in  re- 
lation to  each  distinct  subject  of  inquiry  or  application. 

When  a  letter  concerns  an  application,  it  should  state 
th  e  name  of  the  applicant,  title  of  the  invention, the  serial 
number  of  the  application ,  and  the  date  of  filing  of  same. 

When  a  letter  concerns  a  patent,  it  should  state  the 
name  of  the  patentee,  the  title  of  the  invention  and  the 
number  and  date  of  the  patent. 

APPLICANTS. — A  patent  may  be  obtained  by  any  per- 
son who  has  invented  or  discovered  any  new  or  useful  art, 
machine,  manufacture  or  composition  of  matter;  ,any  new 
and  useful  improvement  thereof,  not  known  or  used  by 
others  in  this  country;  not  patented  or  described  in  any 
publication,  in  this  or  any  foreign  country,  before  his 
invention  or  discovery  thereof,  and  not  in  public  use  or  on 


546 

sale  for  more  than  two  years  prior  to  his  application,  unless 
the  same  is  proved  to  have  been  abandoned;  and  by  any  per- 
son who,  by  his  own  industry,  genius,  efforts,  and  expense, 
has  invented  and  produced  any  new  and  original  design  for  a 
manufacture,  bust,  statue,  alto-relievo  or  bas-relief;  any  new 
and  original  design  for  the  printing  of  woolen,  silk,  cotton,  or 
other  fabrics;  any  new  and  original  impression,  ornament, 
pattern,  print,  or  picture  to  be  printed,  painted,  cast,  or 
otherwise  placed  on  or  worked  into  any  article  of  manufact- 
ure; or  any  new,  useful  and  ornamental  shape  or  configura- 
tion of  any  article  of  manufacture,  the  same  not  having  been 
known  or  used  by  others  before  his  invention  or  production 
thereof,  nor  patented  nor  described  in  any  printed  publica- 
tion, upon  payment  of  the  fees  required  by  law  and  other 
dfoe  proceedings  had. 

In  case  of  death  of  the  inventor,  the  application  may  be 
made  by,  and  the  patent  will  issue  to,  his  executor  or  admin- 
istrator. 

In  case  the  patent  is  to  be  assigned,  the  application  and 
path  must  be  made  by  the  actual  inventor  (not  the  assignee), 
if  alive,  or  his  administrator  or  executor,  if  inventor  is  dead. 

Joint  inventors  are  entitled  to  a  joint  patent;  neither  can 
Claim  one  separately. 

Foreign  patents  will  not  prevent  an  inventor  from  obtain- 
ing one  in  the  United  States,  unless  the  invention  will  have 
been  in  public  use  in  the  United  States  more  than  two  years 
prior  to  the  application. 

But  the  patent, 'if  issued,  will  expire  at  the  same  time  as 
the  foreign  patent. 

THE  APPLICATION. — Applications  for  letters  patent  must 
be  made  to  the  Commissioner  of  Patents. 
.    A  complete  application  comprises  tfa  petition,  specification, 
oath,  and  drawings  (or  the  model  or  specimen  if  required), 
and  the  first  fee  of  $15.00. 

The  petition,  specification  and  oath  must  be  written  in  the 
English  language. 

The  application  must  be  completed  and  prepared  for  ex- 
amination within  two  years  after  filing  of  the  petition,  other- 
wise it  will  be  regarded  as  abandoned,  unless  it  is  shown,  to 
the  satisfaction  of  the  commissioners,  that  the  delay  was  un- 
avoidable. 


547 

THE  PETITION. — The  petition  is  a  communication  duly 
signed  by  the  applicant  and  addressed  to  the  Commissioner  of 
Patents,  stating  the  name  and  residence  of  the  petitioner,  and 
requesting  the  grant  of  a  patent  for  the  invention  therein 
designated  by  name,  with  a  reference  to  the  specifications  for 
a  full  disclosure  thereof. 

The  following  form  will  serve  as  a  model: 

To  the  Commissioner  of  Patents- 

Your  petitioner  (name),  a  citizen  of  the  United  States^ 
residing  at  (name  of  town),  in  the  county  of  (name  of  county), 
and  State  of  (name  of  State),  prays  that  letters  patent  be 
granted  to  him  for  the  improvement  in  (subject  of  invention) 
set  forth  in  the  annexed  specification. 

(Arame  of  Inventor.) 

THE  SPECIFICATION. — The  specification  is  a  written 
description  of  the  invention  or  discovery,  and  of  the  manner 
and  process  of  making,  constructing,  compounding  and  using 
the  same,  and  it  must  be  written  in  such  full,  clear,  concise 
and  exact  terms,  that  anybody  skilled  in  the  art  or  science 
to  which  it  appertains,  or  with  which  it  is  most  nearly  con- 
nected, can  make,  construct,  compound  and  use  the  same. 

It  must  conclude  with  a  specific  and  distinct  claim  or 
claims  of  the  part,  improvement  or  combination  which  the 
applicant  regards  as  his  invention  or  discovery. 

The  following  order  of  arrangement  should  be  observed  in 
framing  the  specification: 

1.  Preamble,  giving  the  name  and  residence  of  the  applicant 
and  the  title  of  the  invention;  and  if  the  invention  has  been 
patented  in  any  country,  a  statement  of  the  country  or  coun- 
tries in  which  it  has  been  so  patented,  giving  the  date  and  num- 
of  each  patent.     If  the  patent  has  no  number  it  will  be  so 
stated  under  oath. 

2.  General  statement  of  the  object  and  nature  of  the  inven- 
tion. 

3.  Brief  description  of  the  drawings,  showing  what  each 
view  represents. 

4.  Detailed  description,  explaining  fully  the  alleged  inven- 
tion, and  the  manner  of  constructing,  practicing,  operating 
and  using  it. 

5.  Claim  or  claims. 

6.  Signature  of  inventor. 

7.  Signature  of  two  witnesses. 


548 

^  The  detailed  description  must  set  forth  the  precise  inven- 
tion  for  which  a  patent  is  claimed,  fully  explaining  the  prin- 
ciple thereof  and  the  best  mode  in  which  the  applicant  has 
contemplated  applying  that  principle^so  as  to  distinguish  it 
from  other  inventions. 

Where  there  are  drawings,  the  description  will  refer  by 
figures  to  the  different  views,  and  by  letters  or  figures  to  the 
different  parts. 

In  every  original  application  the  applicant  must  state,  under 
oath,  whether  the  invention  has  been  patented  to  himself  or 
others,  with  his  consent  and  knowledge,  in  any  country;  if  so,, 
the  names  of  the  country  or  countries,  the  date  and  numbev 
of  each  patent  must  be  given. 

Two  or  more  independent  inventions  cannot  be  claimed  in 
one  application. 

The  specification  must  be  signed  by  the  inventor  or  by  his 
executor  or  administrator,  and  two  witnesses  must  attest  the 
signature.  Full  names  must  be  given,  and  all  names  must  be 
legibly  written. 

The  specification  (and  in  fact  all  documents  relative  to  the 
invention)  must  be  legibly  written,  on  but  one  side  of  the 
paper,  otherwise  the  office  may  require  that  they  be  printed. 

All  interlineations  and  erasures  must  be  clearly  marked  in 
marginal  or  foot  notes  written  on  the  same  sheet  of  paper. 

Legal  cap  paper,  with  the  lines  numbered,  is  best. 

Preserve  a  wide  margin  on  the  left  hand-side  of  the  page. 

THE  OATH. — The  oath  must  follow  the  specification,  and 
should  be  as  follows : 

STATE  OF ,  County  of ,  ss. : 

,    the    above-named    petitioner,    citizen     of 

-,  and  resident  of ,  in  the  county  of  - 


and  State  of ,  being  duly  sworn  (or  affirmed),  depose 

and  say  that verily  believe to  be  the  original, 

first  and  inventor     of  the  improvement  in  

described  and  claimed  in  the  foregoing  specification;  that 

the  same  has  not  been  patented  to ,  or  to  others  with 

knowledge  or  consent,  except  in  the  following  coun- 
tries:   , , — ;  that  the  same  has  not  to 

knowledge  been  in  public  use  or  on  sale  in  the  United  States 
for  more  than  two  years  prior  to  this  application,  and 


549 

do        not  know  and  do        not  believe  that  the  same  was 

ever  known  or  used  prior  to invention  thereof. 

(Inventor's  name  in  full) . 

Sworn    to    and    subscribed   before   me   this   day 

of ,  1 8 . 

[L.  s.]      (Signature  of  justice  or  notary) , 

(Official  character) . 

N.  B.:  If  not  previously  patented,  erase  the  words, 
"except  in  the  following  countries/' and  insert  the  words 
"  in  any  country. " 

If  the  applicant  is  an  alien,  the  oath  will  show  of  what 
foreign  state  or  sovereign  he  is  a  citizen  or  subject. 

If  the  applicants  claim  to  be  joint  inventors,  the  oath  will 
show  "  that  they  verily  believe  themselves  to  be  the  original, 
first  and  joint  inventors,  etc. " 

THE  DRAWINGS. — Applicants  for  patents  must  furnish 
drawings  when  the  nature  of  the  case  admits. 

Drawings  must  be  signed  by  the  inventor  or  his  attorney, 
and  attested  by  two  witnesses. 

The  drawing  must  show  every  feature  of  the  invention 
covered  by  the  claims. 

When  the  invention  consists  of  an  improvement  of  an  old 
machine,  the  drawing  must  exhibit,  in  one  or  more  views,  the 
invention  itself,  disconnected  from  the  old  structure,  and 
also,  in  another  view,  so  much  of  the  old  structure  as  will 
suffice  to  show  the  connection  of  the  invention. 

The  following  rules  are  rigidly  enforced  by  the  patent 
office : 

1.  Drawing*,  must  be  made  upon  pure  white  paper,  of  a 
thickness  corresponding  to  three-sheet  Bristol  board. 

The  surface  of  the  paper  must  be  calendered  and  smooth. 
India  ink  alone  must  be  used,  to  secure  perfectly  black  and 
solid  lines. 

2.  The  size  of  a  sheet  on  which  a  drawing  is  made  must  be 
exactly  10  by  15  inches. 

One  inch  from  its  edge,  a  single  marginal  line  to  be  drawn, 
leaving  the  "  sight,"  precisely  eight  by  thirteen  inches. 

Within  this  margin,  all  work  and  signatures  must  be 
included. 

One  of  the  shorter  sides  of  the  sheet  is  regarded  as  its  top, 
and  measuring  downward  from  the  marginal  line,  a  space  of 


550 
4 

not  less  than  one  and  one-fourth  inch  is  to  be  left  blank  for 
the  heading  of  title,  name,  number  and  date. 

3.  All  drawings  must  be  made  with  the  pen  only. 

Every  line  and  letter  (signature  included)  must  be  absolu- 
tely black. 

These  directions  apply  to  all  lines,  however  fine,  to  shad- 
ing, and  to  lines  representing  cut  surfaces  in  sectional  views. 

All  lines  must  be  clear,  sharp  and  solid,  and  they  must  not 
be  too  fine  or  crowded. 

Surface  shading,  when  used,  should  be  open. 

Sectional  shading  should  be  made  by  oblique  parallel  lines, 
which  may  be  about  one-twentieth  of  an  inch  apart. 

4.  Drawings  should  be  made  with  the  fewest  lines  possible 
consistent  with  clearness. 

Shading  (except  on  sectional  views)  should  be  used  only  on 
convex  and  concave  surfaces,  and  then  sparingly. 

The  plane  upon  which  a  sectional  view  is  taken  should  be 
indicated  on  the  ground  view  by  a  broken  or  dotted  line. 

Heavy  lines  on  the  shade  sides  of  objects  should  be  used, 
except  when  they  tend  to  thicken  the  work  and  obscure  letters 
of  referrance. 

The  light  is  always  supposed  to  come  from  the  upper  left 
hand  corner,  at  an  angle  of  forty-five  degrees. 

Imitations  of  wood  or  surface-graining  should  not  be 
attempted. 

5.  The  scale  upon   which  the  drawing  is  made  must  be 
large  enough  to  show  the  mechanism  without  crowding. 

If  one  sheet  is  not  enough,  use  more. 

6.  Form  the  letters  and    figures   of  reference   carefully; 
make  them,  if  possible,  at  least  J/%  of  an  inch  in  height. 

Do  not  draw  figures  and  letters  on  the  lines  of  the 
drawings. 

Never  place  them  in  shaded  places. 

Never  use  the  same  letter  or  figure  to  represent  more  than 
one  part. 

The  signature  of  the  inventor  must  be  placed  at  the  lower 
right-hand  corner  of  the  sheet,  and  the  signatures  of  witnesses 
at  the  lower  left-hand  corner,  all  within  the  marginal  lines. 

The  title  must  be  written  in  pencil  on  the  back  of  the 
sheet. 

Drawings  should  be  rolled  for  transmission  to  the  patent 
office,  never  folded. 


The  patent  office  advises  inventors  to  employ  a  competent 
artist  to  make  their  drawings.  The  patent  office  will  do  the 
work  at  cost. 

THE  MODEL. — A  working  model  is  often  desirable  in 
order  that  the  patent  office  may  fully  and  readily  understand 
the  precise  operation  of  the  machine. 

It  must  not  be  over  one  foot  in  length,  width  or  height. 

It  must  be  neatly  and  substantially  made,  of  durable  mate- 
rial, metal  preferred. 

If  made  of  wood,  it  must  be  painted  or  varnished. 

Glue  must  not  be  used,  but  the  parts  must  be  constructed 
to  resist  heat  and  moisture. 

It  must  clearly  exhibit  every  feature  of  the  machine  which 
forms  the  subject  of  a  claim  of  invention,  but  should  not 
include  other  matter  than  that  covered  by  the  actual  inven- 
tion or  improvement,  unless  it  is  necessary  for  exhibiting  the 
invention  in  a  working  model. 

ATTORNEYS. — It  is  always  best  to  employ  a  competent 
patent  lawyer  as  attorney.  The  inventor  can  then  be  as- 
sured that  all  the  formalities  and  regulations  of  the  Patent 
Office  are  being  complied  with. 

The  lawyer  will  see  that  the  drawings  and  models  meet  the 
requirements  of  the  Patent  Office,  and  he  can  urge  the  matter 
to  a  speedier  termination  than  the  inventor  can  do,  if  acting 
himself. 

CONSULT  A  GOOD  PATENT  LAWYER. 
The  Patent  Office  fee  for  filing  each  original  appli- 
cation for  a  patent  is $15  °o 

On  issue  of  letters  patent 20  oo 

On  filing  a  caveat ; 10  oo 

On  filing  a  disclaimer 10  oo 

On  filing  application  for  re-issue  of  a  patent 30  oo 

On  filing  application  for  a  division  of  a  re-issue. ....     30  oo 

On  filing  application  for  extension  of  a  patent 50  oo 

On  granting  extension 50  oo 


552 
HOW  STEEL  RULES  ARE  MADE. 

There  are  few  branches  of  the  engineering  trades  that 
require  the  exactness  and  precision  requisite  in  the  manufact- 
ure of  steel  rules,  standards,  and  measuring  instruments. 

Accuracy  and  reliability  are  the  two  absolute  essentials.  In 
the  general  practice  the  steel  blades,  after  being  prepared  by 
being  ground,  glazed,  and  tempered,  are  coated  by  an  acid- 
resisting  varnish,  specially  made  to  suit  the  requirements  of 
the  trade,  for  upon  this  depends,  in  a  great  measure,  the 
clearness  of  the  divisions  when  etched.  The  varnish  being 
dry,  the  blades  are  placed  upon  the  table  of  a  pentagraph, 
which  might  well  be  termed  a  copying  machine,  as  its  work  is 
to  transfer  to  the  steel  blades,  in  a  diminished  size,  any  marks, 
letters,  or  figures  that  may  be  traced  ftom  the  copy.  The 
latter  is  a  plate  of  thin  zinc,  or  any  suitable  metal,  usually 
four  times  larger  than  the  rules  to  be  made,  the  divisions, 
figures,  and  letters  all  being  made  four  times  larger  than  they 
are  required  to  be  when  engraved  upon  the  steel  blades;  the 
•bject  of  this  increased  size  being  to  diminish  any  imperfec- 
tion that  may  exist  upon  the  copy.  There  is  a  tracer  con- 
nected by  a  system  of  steel  bands  and  pulleys  to  the  table  so 
constructed  as  to  move  in  two  opposite  directions  at  right 
angles  to  each  other.  Above  the  table  are  fixed  two  rows  of 
holders,  each  having  a  diamond  point;  these  holders  are  raised 
and  lowered  at  the  will  of  the  operator  by  a  treadle,  so  that 
both  divisions,  figures,  and  letters  are  traced  from  the  copy 
and  transferred,  in  a  diminished  proportion,  to  the  steel 
blades.  The  diamond  points  being  required  only  to  cut 
through  the  varnish,  the  blades  are  taken  from  the  machine 
and  etched,  the  acid  burning  away  the  steel  wherever  the 
diamond  point  has  been  traced. 


WHAT  INVENTION  HAS  DONE. 

In  the  manufacture  of  boots  and  shoes,  the  work  ot  500 
operatives  is  now  done  by  100. 

In  making  bread  boxes,  three  workers  can  do  the  work  of 
thirteen  box  makers  by  old  methods. 

In  cutting  out  clothing  and  cloth  caps  with  discs,  one 
worker  does  the  work  of  three  by  the  old  methods. 


553 

In  leather  manufacture  modern  methods  have  reduced  the 
necessary  number  of  workers  from  5  to  50  per  cent. 

A  carpet  measuring  and  brushing  machine  with  one 
operator,  will  do  the  work  of  fifteen  men  by  the  old  methods. 

In  the  manufacture  of  flour,  modern  improvements  save 
75  per  cent,  of  the  manual  labor  that  once  was  necessary. 

By  the  use  of  coal-mining  machines,  100  miners,  in  a 
month,  can  mine  as  much  coal  as  500  miners  by  the  old 
methods. 

In  making  tin  cans,  one  man  and  a  boy,  with  modern 
appliances,  can  do  the  work  of  ten  workers  by  the  old  proc- 
esses. 

One  boy,  by  machinery  in  turning  wood-work  and  materials 
for  musical  instruments,  performs  the  work  of  twenty-five 
men  by  the  old  methods. 

The  horse-power  steam  used  in  the  United  States  on  rail- 
ways, steamers,  and  in  the  factories  and  mines  was,  in  1888, 
12,100,000,  against  1,610,000  in  1850. 

In  the  manufacture  of  bricks,  improved  devices  save  one- 
tenth  of  the  labor;  and  in  manufacturing  of  fire  brick,  40  per 
cent,  of  the  manual  labor  is  displaced. 


534 


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HOW  TO  DETECT  GAS  LEAKAGE. 

In  order  to  detect  gas  leakage,  Dr.  Bunte,  in  the 
Canadian  Magazine  of  Science^  suggests  the  use  of  paper 
dipped  in  palladium  chloride  solution.  Such  paper  changes 
its  color  in  presence  of  gas  coming  from  the  leaks  imper- 
ceptible by  the  odor,  and  which  produce  no  effect  upon  the 
earth  covering  the  pipes.  Dr.  Bunte  suggests  the  following 
method  of  practically  applying  the  test  to  street  mains : 
Above  the  pipes  are  excavated,  at  intervals  of  two  or  three 
yards,  holes  twelve  to  sixteen  inches  deep,  corresponding  to 
the  joints  and  sleeves.  In  each  opening  is  placed  an  iron 
tube,  half  an  inch  in  diameter,  within  which  is  a  glass  tube, 
containing  a  roll  of  the  test  paper.  The  air  from  about  the 
main  enters  the  iron  tube,  and  the  trace  of  gas  which  may  be 
present  reveals  itself  by  coloring  the  paper  brown  or  black, 
according  to  the  quantity.  If,  after  ten  or  twenty  minutes, 
the  paper  is  still  white,  it  may  be  certainly  concluded  that  at 
the  point  tested  there  is  not  the  smallest  escape  of  gas. 
Various  author-ities  who  have  experimented  with  Bunte's 
method  certify  vO  its  efficacy. 


556 
POINTERS  ON  SUCCESS  IN    BUSINESS. 

Buy  and  sell  for  cash. 

Don't  try  to  start  in  a  big  way. 

Morality  is  the  basis  of  co-operation. 

Require  all  employes  who  handle  funds  to  give  bonds. 

Confidence  in  one  another  is  the  natural  outgrowth  of 
sound  morality. 

By  doing  a  cash  business  every  workingman's  dollar  is 
worth  $1.10. 

Co-operation  will  insure  a  good  article,  and  honest  weights 
and  measures. 

Beware  of  credit.  He  is  the  undertaker  who  buries  all 
foolish  co-operators. 

Never  imagine  your  work  is  done.  Eternal  vigilance  is 
the  price  of  success. 

The  primary  object  of  co-operation  is  to  improve  the 
condition  of  producers. 

Don't  make  your  by-laws  too  long  or  technical,  and  com- 
pel their  close  observance. 

The  backbiter  and  slanderer  is  the  most  dangerous  per- 
son you  can  get  into  a  co-operative  society. 
^'Seeto  it  that  your  manager  makes  statements  quarterly, 
or  as  the  by-laws  provide,  and  be  on  hand  to  hear  them,  in- 
stead of  staying  away  and  grumbling. 

Keep  clear  of  all  political  party  manipulators ;  long  be- 
fore you  fully  understand  the  science  of  industrial  co-opera- 
tion, you  will  know  how  to  co-operate  at  the  ballot  box. 

Intelligence,  sobriety,  industry  and  economy  are  indis- 
pensable requisites  of  co-operators.  Co-operation  can  do 
nothing  for  the  lazy,  immoral  or  reckless,  unless  they  reform. 

Put  your  enterprise,  no  matter  what  it  is,  in  the  hands  of 
a  man  who  understands  the  business.  If  you  attempt  to  learn 
co-operation  and  educate  a  manager  in  the  conduct  of  the 
business  at  the  same  time,  you  will  fail. 

When  you  select  a  manager  let  him  run  the  business  until 
he  demonstrates  his  incapability.  More  enterprises  fail 
through  the  meddling  of  a  bad  board  in  things  they  don't 
understand  than  from  any  other  single  cause. 

Take  the  bold  step  of  gradually  reducing  stock. 

Seize  the  right  time  for  modifying  your  business  with  ad- 
vantage. 

Push  your  trade  with  energy  and  spirit,  and  by  judicious 
advertising. 

Divide  your  risks  as  the  insurance  people  do,  so  that  in 
*ase  of  failure  you  will  not  be  much  hurt . 


557 

In  stock-taking  let  nothing  but  real  value  appear  in  the 
balance  sheet,  and  under  rather  than  over  value. 

Let  the  benefit  to  accrue  from  vigorous  use  of  the  prun- 
ing knife  sustain  you.  It  will  come  out  all  right  in  the  end. 

As  a  rule  you  lose  people  and  their  custom  when  they  get 
into  your  debt.  If  possible  do  a  strictly  cash  business. 

Strike  off  all  customers  who  will  not  steadily  pay  monthly. 
Keep  strictly  to  this  rule  and  you  will  have  a  healthy  trade. 

The  true  limits  of  credit  may  be  seen  from  the  etymology 
of  the  word.  It  is  a  promise  to  pay  something  in  the  future. 

When  you  have  commenced  a  business  go  thoroughly  into  it. 
Do  not  be  ashamed  of  an  honest  business  that  is  supporting 
you.  Make  it  honorable. 

When  an  account  is  opened  ask  the  parties  to  what  extent 
they  wish  to  go  and  keep  them  to  the  amount  agreed  upon, 
which,  with  their  name,  should  be  entered  in  the  ledger. 

VARIOUS    LOCATIONS    OF     THE     CAPITAL    OF 
THE  UNITED   STATES. 

The  capital  of  the  United  States  has  been  located  at  dif- 
ferent times  at  the  following  places:  At  Philadelphia 
from  September  5,  1774,  until  December,  1776;  at 
Baltimore  from  December  20,  1776,  to  March,  1777;  at 
Philadelphia  from  March  4, 1777,  to  September,  1777;  at  Lan- 
caster, Pa.,  from  September  27,  1777, to  September  30,  1777; 
at  York,  Pa.,  from  September  30,  1777,  to  July,  1778;  at 
Philadelphia  from  July  2,  1778,  to  June  30,  1783;  at  Prince- 
ton, N.  J.,  June  30,  1783,  to  November  20,  1783;  Annapo- 
lis, Md. ,  November  26,  1783,  to  November  30,  1784; 
Trenton  from  November,  1784,  to  January,  1785;  New 
York  from  January  n,  1785,  to  1790;  then  the  seat  of  gov- 
ernment was  removed  to  Philadelphia,  where  it  remained 
until  1800,  since  which  time  it  has  been  at  Washington. 

GROWTH  OF   THE  UNITED  STATES. 

The  United  States  has  a  population  of  at  least  62,000,000 
at  this  moment.  This  makes  it  second  in  this  particular 
among  the  great  civilized  nations  of  the  world.  Keeping  in 
view  the  ratio  of  growth  of  the  countries  named  between 
recent  census  periods,  there  are  to-day  about  88,000,000 
inhabitants  in  European  Russia,  47,000,000  in  Germany,  40,- 
000,000  in  Austro- Hungary,  38,000,000  in  France,  37,000,000 
in  Great  Britain  and  Ireland,  30,000,000  in  Italv.  anJ.  r??* 
000,000  in  Spain- 


The  population  of  none  of  the  other  countries  in  Europe 
reaches  10,000,000  —  Turkey's  inhabitants  outside  of  Asia 
aggregating  scarcely  half  that  figure.  Russia  alone  of  the 
great  powers  of  Christendom  exceeds  the  United  States  in 
population.  Even  Russia  must  soon  be  left  far  in  the  rear. 
July  i,  1890,  when  the  next  national  enumeration  takes  place, 
the  United  States  will  have  67,000,000  inhabitants.  It  will 
have  96,000,000  in  the  year  1900,  and  124,000,000111  1910. 
This  computation  is  based  on  the  average  growth  of  the 
country  during  the  century.  Employing  a  like  basis  for 
Russia,  that  nation  before  1910  will  have  dropped  to  second 
place,  the  United  States  taking  the  first. 

Forty  years  ago  the  United  States  stood  sixth  in  point  of 
population  among  civilized  nations  of  the  globe  and  twenty 
years  ago  it  stood  fifth.  Twenty  years  hence  it  will  stand 
first. 

THE  NEW  FORTH   BRIDGE. 

The  new  railroad  bridge  over  the  Frith  of  Forth,  in 
Scotland,  to  replace  the  one  which  went  down  with  such 
appalling  results  a  few  years  ago,  is  now  near  completion,  and 
is  described  as  one  of  the  finest  pieces  of  engineering  in  the 
world.  The  chief  engineer  of  the  structure  gives  the  follow- 
ing "cold  facts"  regarding  it:  The  total  length  of  the 
viaduct  will  be  8,296  feet,  or  nearly  i^  miles,  and  there  are 
two  spans  1,710  feet,  two  of  680  feet,  fifteen  of  168  feet 
girders,  four  of  57  feet,  and  three  of  25  feet,  being  masonry 
arches.  The  clear  headway  for  navigation  will  not  be  less 
than  150  feet  for  500  feet  in  the  center  of  the  1,710  feet  spans. 
The  extreme  height  of  the  structure  is  361  feet  above,  and 
the  extreme  .depths  of  foundation  91  feet  below  the  level  of 
high  water.  There  will  be  about  53,000  tons  of  steel  in  the 
superstructure  of  the  viaduct,  and  the  material  used  through- 
out is  open-hearth  of  Siemens-Martin  steel.  That  used  for 
parts  subject  to  tension  is  specified  to  withstand  a  tensile 
stress  of  30  to  33  tons  to  the  square  inch  with  an  elongation 
in  eight  inches  of  not  less  than  20  per  cent. ;  that  subject  to 
compression  only  a  tensile  stress  of  34  to  37  tons  per  square 
inch,  with  an  elongation  in  eight  inches  of  not  less  than  17 
per  cent. 

Rochester,  N.  Y.,  has  an  electric-light  plant  which  sup- 
plies i, too  arc  and  1,025  incandescent  lamps.  The  plant  is 
said  to  be  the  largest  in  the  world  run  by  water  power- 


559 
"ANCIENT"    WINTERS. 

In  401  the  Black  Sea  was  entirely  frozen  over.  In  763 
not  only  the  Black  Sea,  but  the  Straits  of  Dardanelle,  were 
frozen  over,  the  snow  in  some  places  rising  50  feet  high.  In 
822  the  great  rivers  of  Europe,  the  Danube,  the  Elbe,  etc., 
were  so  hard  frozen  as  to  bear  heavy  wagons  for  a  month. 
In  860  the  Adriatic  was  frozen.  In  991  everything  was 
frozen,  the  crops  totally  failed  and  famine  and  pestilence 
closed  the  year.  In  1707  most  of  the  travelers  in  Germany 
were  frozen  to  death  on  the  roads.  In  1 134  the  Po  was 
frozen  from  Cremona  to  the  sea,  the  wine  sacks  were  burst, 
and  the  trees  split  by  the  action  of  the  frost  with  immense 
noise.  In  1236  the  Danube  was  frozen  to  the  bottom,  and 
remained  long  in  that  state.  In  1316  the  crops  wholly  failed 
in  Germany.  Wheat,  which  some  years  before  sold  in 
England  at  6s.  the  quarter,  rose  to  £2.  In  1308  the  crops 
failed  in  Scotland,  and  such  famine  ensued  that  the  poor  were 
reduced  to  feed  on  grass,  and  many  perished  miserably  in  the 
fields.  In  1368  the  wine  distributed  to  the  soldiers  was  cut 
with  hatchets.  The  successive  winters  of  1432-3-4  were 
uncommonly  severe.  In  1663  it  was  excessively  cold.  Most 
of  the  hollies  were  killed.  Coaches  drove  along  the  Thames, 
the  ice  of  which  was  n  inches  thick.  In  1709  occurred  very 
clod  weather ;  the  frost  penetrated  three  yards  into  the  ground. 
In  1 726  booths  were  erected  on  the  Thames.  In  1744  and 
1745  the  strongest  ale  in  England,  exposed  to  the  air,  was 
covered  in  less  than  15  minutes  with  ice  an  eighth  of  an  inch 
thick.  In  1808  and  again  in  1812*,  the  winters  were  remark- 
ably cold.  In  1814  there  was  a  fair  on  the  frozen  Thames. 

STRENGTH  OF  HORSES. 

It  is  stated  that,  if  one  horse  can  draw  a  certain  load  over 
a  level  road  on  iron  rails,  it  will  take  one  and  two-thirds  horses 
to  draw  the  same  load  on  asphalt,  three  and  one-third  horses 
to  draw  it  on  the  best  Belgian  block,  five  on  the  ordinary 
Belgian  pavement,  seven  on  good  cobblestones,  thirteen  on 
bad  cobblestones,  twenty  on.  an  ordinary  earth  road,  and  forty 
©n  a  sandy  road. 

THE  LARGEST  DAM  IN  THE  WORLD. 

The  largest  dam  in  the  world  is  in  California.  It  will  be 
700  feet  long,  175  feet  high,  175  feet  thick  at  the  base,  20 
feet  thick  at  the  top,  and  the  reservoir  thus  formed  wild  haw 
&  capacity  of  32,000.000  gallon* 


56o 

THE  LARGEST  PONTOON  BRIDGE  IN 
WORLD. 

The  pontoon  bridge  over  the  Missouri  River  at  Nebraska 
City  is  said  to  be  the  largest  in  the  world.  Its  length  across 
the  navigable  channel  is  1,074  feet,  while  the  back  channel  is 
traversed  by  a  causeway  1,050  feet  long,  supported  on  cribs. 
The  charter  for  this  bridge  has  been  held  for  twelve  years, 
because  of  the  difficulty  of  obtaining  financial  support  for  a 
project  that  appeared  so  impracticable.  It  is  stated  that  the 
entire  bridge  was  built  in  twenty-eight  days,  at  a  cost  not 
exceeding  $18,000,  by  Col.  S.  N.  Stewart  of  Philadelphia, 
assisted  by  Gen.  Lyman  Banks,  of  Iowa.  The  draw  is 
V-shaped,  with  the  apex  downstream.  It  is  operated  by  the 
current  and  controlled  by  one  man.  The  clear  span  is  528 
feet,  the  largest  in  the  world.  The  bridge  was  completed  in 
August,  and  is  doing  good  service.  It  will  be  removed 
during  the  ice  season. 

THE|  BANK  OF  ENGLAND  DOORS. 

The  Bank  of  England  doors  are  now  so  finely  balanced 
that  a  clerk,  by  pressing  a  knob  under  his  desk,  can  close  the 
outer  doors  instantly,  and  they  cannot  be  opened  again  exc-ept 
by  special  process.  This  is  done  to  prevent  the  daring  and 
ingenious  unemployed  of  the  metropolis  from  robbing  the 
bank.  The  bullion  departments  of  this  and  other  banks  are 
nightly  submerged  several  feet  in  water  by  the  action  of  the 
machinery.  In  some  bank* the  bullion  department  is  con- 
nected with  the  manager's  sleeping  room,  and  an  entrance 
cannot  be  effected  without  shooting  a  bolt  in  the  dormitory, 
which  in  turn  sets  in  motion  an  alarm.  If  a  visitor,  during 
the  day,  should  happen  to  knock  off  one  from  a  pile  of  half 
sovereigns  the  whole  pile  would  disappear,  a  pool  of  water 
taking  its  place. 

NEW  SUBSTITUTE  FOR   LEATHER. 

Dr.  George  Thenius,  in  Vienna,  has  a  process  for  the 
manufacture  of  artificial  leather  from  red  beechwood.  The 
best  wood  for  the  purpose  is  taken  from  fifty  to  sixty  years  old 
trees,  cux  :^  jtfoe  /Spring,  and  must  be  worked  up  immediately, 
bark  peeled  off,  steamed,  tr^ted  &#&  cbsmicaU  aaa  a  kettle 
under  pressure,  and  then  exposed  to  several  more  operations, 
which  the  inventor  does  not  mention,  as  he  wants  to  have 
them  patented. 

From  the  prepared  wood  strong  and  thin  pieces  are  made 


by  means  of  heavy  pressure.  The  inventor  states  that  a  solid 
sole  leather  can  be  obtained,  which  he  claims  is  superior  t :> 
the  animal  leather  in  firmness  and  durability,  and  can  be 
worked  up  in  the  same  way  as  animal  leather,  nailed  and 
5ewed.  We  do  not  believe  that  the  leather  industry  needs  to 
fear  the  artificial  product. 

THE  USELESSNESS  OF  LIGHTNING  RODS. 

The  uselessness  of  the  lightning  rod  is  becoming  so  gen- 
erally understood  that  the  agents  find  their  vocation  a  trying 
one.  Fewer  and  fewer  rods  are  manufactured  each  year,  and 
"  the  day  will  come  when  a  lightning  rod  on  a  house  will  be 
regarded  in  the  same  light  as  a  horseshoe  over  a  man's 

THE  WELLAND  CANAL. 

The  enlarged  Welland  Canal  is  regarded  as  one  of  the 
grandest  exhibitions  of  engineering  skill  in  the  world.  The 
water  level  of  Lake  Erie  is  over  300  feet  higher  than  that  of 
Lake  Ontario,  and  this  canal  has  been  built  to  allow  loaded 
ships  to  pass  from  one  lake  to  the  other.  For  this  passage 
28  miles  of  canal  and  26  locks  are  required.  The  small  village 
of  Port  Colborne  stands  at  the  entrance  of  the  canal.  The 
first  lock  is  built  near  the  entrance,  to  keep  back  the  swash- 
ing sea,  after  which  comes  a  stretch  of  14  miles  through  a 
farming  country  to  the  second  lock,  after  which  the  locks  are 
located  about  as  thick  as  possible  until  Lake  Ontario  is 
reached.  The  greater  part  of  the  descent  is  in  the  upper 
half  mile  of  the  route,  and  it  takes  about  13  hours  to  get 
through  the  canal  with  no  hindrances. 

A  VALUABLE  POINT  FOR  PAPER-MAKERS. 

Iron  is  apt  to  discolor  paper  by  rusting  after  it  has  been 
abraded  from  the  paper-making  machinery.  Magnetism  has, 
therefore,  been  called  in  by  a  German  manufacturer  to  clear 
away  the  iron  specks.  A  series  of  magnets  are  arranged  in 
the  form  of  a  comb  and  hung  across  the  stream  of  pulp  and 
water,  which,  in  passing  the  magnetic  teeth  of  the  comb, 
delivers  up  the  iron  particles. 

HOW  TO  DRIVE  A^CLE  THROUGH  GLASS. 
Iz.  drilling  glass,  stick  a  piece  of  stiff  clay  or  putty  on  the 
part  where  you  wish  to  make  the  hole.  Make  a  hole  in  the 
putty  the  size  you  want  the  hole,  reaching  to  the  glass,  of 
course.  Into  this  hole  pour  a  little  molten  lead,  when,  unless 
it  is  very  thick  glass,  the  piece  will  immediately  drop  out. 


562 
THE  LARGEST  LOCK  IN  THE  WORLD. 

The  Sault  Ste.  Marie  canal  has  the  second  largest  lock  in 
the  world.  It  is  built  of  solid  masonry,  560  feet  long,  80 
feet  wide,  with  walls  40  feet  high,  the  lift  18  feet,  and  the 
depth  of  I  he  water  in  the  basin  1 6  feet.  This  lock  belongs 
to  the  United  States  Government  and  cost  $3,000,000,  and 
will  accommodate  four  at  a  time  of  the  largest  vessels  ever 
brought  to  these  waters.  A  new  and  still  larger  lock,  to 
cost  $5,000,000,  is  now  being  constructed.  The  canal  now 
has  a  larger  daily  traffic  than  the  great  Suez  canal. 

HOW  GAMBOGE  IS  PREPARED. 
Gamboge  is  a  gum,  and  an  average  gamboge  tree  is  said 
to  yield  annually  sufficient  to  fill  three  bamboo  cylinders, 
each  about  18  to  20  inches  long  and  il/2  inches  in  diameter. 
It  takes  about  a  month  to  fill  a  cylinder.  When  full  the 
bamboo  is  rotated  over  a  fire  to  allow  the  moisture  to  escape 
and  the  gum  to  harden  sufficiently  to  admit  of  being 
removed. 


7 


A  human  hair  is  10,000  times  larger  than  a  spider's  thread. 

The  taxable  valuation  of  New  York  city,  real  and  per- 
sonal property,  for  1888,  was  $1,553,442,431.66. 

At  Erie,  Pa.,  a  well  has  been  bored  3,500  feet.  The 
Schladeback  boring  was  down  to  4,515  feet. 

A  hammer  for  a  pile-driver,  made  at  Jacksonville,  recently  . 
was  the  largest   ever   cast    in   Florida.     It   weighed    2,350 
pounds. 

Cavendish,  in  1766,  discovered  hydrogen,  and  between 
1774  and  1779  Priestley  discovered  oxygen,  azote  and  nitrous 
gas. 

A  New  York  dealer  says  that  20,000,000  pounds  of  rubber 
comes  to  this  country  every  year  from  Borneo,  Africa,  and 
Para,  South  America. 

The  Chinese  language  is  spoken  by  400,000,000  persons; 
Hindostani  by  upward  of  100,000,000 ;  English  by  more 
than  100,000,000;  Russian  by  more  than  70,000,000;  Ger- 
man by  58,000,000;  Spanish  by  48,000,000,  and  French  by 
only  40,000,000. 


563 
COMMON  NAMES  OF  CHEMICAL  SUBSTANCES 

Aqua  Fortis Nitric  Acid 

Aqua  Kegia Nitro-Muriatic  Acid 

mue  Vitriol Sulphate  of  Copper 

Cream  of  Tartar Bitartrate  of  Potassium 

Calomel Chloride  of  Mercury 

Chalk Carbonate  of  Calcium 

Salt  of  Tartar Carbonate  of  Potassa 

Caustic  Potassa Hydrate  of  Potassium 

Chloroform Chloride  of  G.  ormyle 

Common  Salt Chloride  of  Sodium 

Copperas  or  Green  VitriolSulphate  of  Iron 

Corrosive  Sublimate Bichloride  of  Mercury 

Diamond Pure  Carbon 

Dry  Alum Sulphate  Aluminum  and  Potassium 

Epsom  Salts Sulphate  of  Magnesia 

Ethiops  Mineral Black  Sulphide  of  Mercury 

Fire  Damp Light  Carbureted  Hydrogen 

Galena Sulphide  of  Lead 

Glucose Grape  Sugar 

Goulard  Water Basic  Acetate  of  Lead 

Iron  Pyrites Bisulphide  of  Iron 

Jeweler's  Putty Oxide  of  Tin 

King  Yellow Sulphide  of  Arsenic 

Laughing  Gas Protoxide  of  Nitrogen 

Lime Oxide  of  Calcium 

Lunar  Caustic Nitrate  of  Silver 

Mosaic  Gold Bisulphide  of  Tin 

Muriate  of  Lime Chloride  of  Calcium 

Niter  of  Saltpeter Nitrate  of  Potash 

Oil  of  Vitriol Sulphuric  Acid 

Potash Oxide  of  Potassium 

Red  Lead , Oxide  of  Lead 

Rust  of  Iron Oxide  of  Iron 

Sal  Ammoniac Muriate  of  Ammonia 

Slacked  Lime Hydrate  of  Calcium 

Soda Oxide  of  Sodium 

Spirits  of  Hartshorn.   . . .  Ammonia 

Spirit  of  Salt Hydrochloric  or  Muriatic  Acid 

Stucco,  or  Plaster  Paris.. Sulphate  of  Lime 

Sugar  of  Lead Acetate  of  Lead 

Verdigris Basic  Acetate  of  Copper 

Vermilion Sulphide  of  Mercury 

Vinegar Acetic  Acid  (diluted 

Volatile  Alkali Ammonia 

Water Oxide  of  Hydrogen 

White  Precipitate Ammoniated  Mercury 

White  Vitriol Sulphate  of  Zinc 

AN  IMPROVED  METHOD  OF  MOLDING 
It  is  claimed  that  a  saving,  as  well  as  a  better  job,  can  be 
effected  by  the  substitution  of  the  following  for  the  coal  dust 
and  charcoal  used  with  green  sand:  Take  1  part  common  tar 
and  mix  with  20  of  green  sand ;  use  the  same  as  ordinary  fac- 
ing. The  castings  are  smoothed  and  bright,  as  tar  prevents 
metal  from  adhering  to  the  sand,  formation  of  blisters  and 
helps  large  castings  by  absorbing  the  humidity  of  the  sand. 


564 
HYDRAULIC  BAMS. 

Very  few  persons  understand  the  method  of  raising  water 
by  the  use  of  the  hydraulic  ram,  though  there  are  many 
places  on  the  farm  where  they  can  be  profitably  employed. 
The  invention  is  an  old  one,  and  apparently  comes  near  per- 
petual motion.  The  ram  itself  is  a  pear-shaped  iron  cylinder, 
placed  in  the  ground  at  a*  depth  sufficient  to  protect  it  from 
the  effect  of  frost  in  winter.  The  spring  or  well  which  sup- 
lies  the  water  is  situated  at  some  point  above,  so  that  there 
will  be  a  fall  of  one  foot  for  every  eight  feet  of  perpendicu- 
lar height  to  which  the  water  is  to  be  carried.  For  instance, 
if  it  is  necessary  to  force  water  up  a  hill  to  the  house,  which 
stands  forty-eight  feet  above  the  spring,  the  fall  must  be  at 
least  six  feet  from  the  spring  to  the  ram.  The  horizontal 
distance  has  no  effect  on  the  calculation,  and  it  is  often  car- 
ried hundreds  of  feet,  and  in  some  cases  over  a  thousand. 
The  principle  on  which  the  water  is  forced  up  is  by  com- 
pressed air.  The  water  passes  from  the  spring  in  a  pipe,  say 
two  inches  in  diameter,  against  a  check  valve,  which  is  lifted 
up  by  the  force  of  the  water  until  it  reaches  a  certain  point, 
when  a  portion  of  the  water  is  crowded  by  its  own  weight 
into  the  ram  until  the  air  is  so  compressed  that  it  discharges 
itself  into  a  small  pipe,  say  half  an  inch  in  diameter,  which 
runs  up  the  elevation  to  the  barn,  house  or  wherever  wanted. 
In  well  constructed  rams  the  power  has  been  found  to  be 
about  two-thirds  of  the  energy  of  the  falling  water. 

Wherever  small  quantities  of  water  are  needed,  this  way 
of  supplying  the  want  has  been  found  to  be  very  convenient. 
The  only  thing  that  seems  to  stop  the  working  is  a  failure  of 
the  water  supply.  Night  and  day,  year  after  year,  the  little 
air  engine  works  away,  needing  no  rest,  oil  or  wind,  simply 
water,  and  that  in  abundance.  One  in  Norfolk  county, 
Massachusetts,  has  been  in  operation  for  many  years,  and  is 
still  at  work  supplying  the  owner's  house  and  barn  with 
water.  To  one  who  has  never  seen  its  workings,  it  is  very 
interesting.  No  visible  power  in  sight;  the  little  valve  rises 
to  its  proper  elevation,  remains  there  an  instant,  then  drops 
to  its  base  of  operations,  only  to  start  upward  again,  which 
is  repeated  continually. 


GLOSSORY  OF  TECHNICAL  TERMS. 

ABSOLUTE.     Complete  in  itself. 

Unit  of  Current.     A  current  of  ten  ampe*res. 
Unit  of  Electromotive  Force.     The  one   hundred  mill- 
ionth of  a  volt. 

Unit  of  Resistance.     The  one  thousand  millionth  of  an 
ohm. 

ACCELERATION.  Change  in  the  velocity  of  a  moving  body, 
either  an  increase  or  decrease,  constant  or  variable. 

ACCUMULATOR.  A  secondary  or  storage  battery — a  Leyden 
jar 

ACHROMATIC. — Without  false  coloration ;  a  lens  is  achromatic 
when  it  is  free  from  color  and  does  not  produce  pris- 
matic fringes  in  the  image  or  object  formed. 

ACLINIC  LINE.  The  line  on  the  earth's  surface  connecting 
those  places  where  the  magnetic  needle  has  no  incli- 
nation or  dip — the  magnetic  equator. 

ACOUSTICS.  That  branch  of  natural  law  which  treats  of 
sound. 

ACTINISM.  The  property  or  power  possessed  by  the  sun's 
rays  to  produce  a  chemical  effect  or  decomposition  (as 
shown  in  photography). 

ACTION,  LOCAL.  The  chemical  action  which  takes  place  in 
a  primary  battery,  and  which  consumes  the  zinc  with- 
out generating  a  working  current. 

ACTIVITY.     Work  done  per  second  by  any  agent. 

ADHESION.  The  force  by  which  particles  of  different  and 
unlike  bodies  stick  together. 

AFFINITY.  (Chemical).  The  force  which  combines  to- 
gether chemical  elements  to  form  compounds,  some- 
times termed  "  chemical  attraction" 

AGOUR.  The  line  on  the  earth's  surface  of  no  declination 
or  variation  of  a  magnetic  needle. 

ALLOY.  A  mixture  or  combination  of  two  or  more  metallic 
substances. 

ALTERNATING.     A  motion  up  and  down,  or  backward  and 

forward,  instead  of  revolving. 

Current.     An  electric  current  which  alternately  flows  in 
opposite  directions. 

AMALGAM.     The  combination  of  a  metal  with  mercury. 

AMORPHOUS.     Without  definite  crystalline  form. 


566 

AMPERE.  The  unit  of  strength  of  an  electric  current.  The 
practical  unit  ot  an  electrical  current.  The  ampere 
represents  a  current  produced  by  the  electromotive, 
force  of  one  volt  passing  through  a  circuit  whose  resist- 
ance is  equal  to  one  ohm.  In  other  words,  the  am- 
pere represents  the  volume  of  electricity,  the  volt  the 
pressure,  and  the  ohm  the  resistance  encountered. 

AM-METER.  A  device -used  for  measuring  the  strength  of  an 
electrical  current  in  amperes. 

ANALYSIS.  The  process  of  determining  the  composition  of 
a  compound  substance  by  dividing  it  into  the  simple, 
elements  of  which  it  is  composed.  Chemical  analysis 
is  qualitative  when  it  determines  the  kind  of  the  simple 
elements;  it  is  qualitative  when  it  ascertains  the  rela- 
tive proportions  of  these  simple  elements. 

ANGLE.  The  opening  formed  by  two  lines  drawn  in  different 
directions  on  a  plane  surface,  meeting  or  intersecting. 

ANODE.     The  positive  pole  or  etectrode  of  a  battery. 

ANOMALOUS  MAGNET.  A  magnet  which  has  more  that  two 
free  poles. 

ARC.  The  opening  or  space  between  two  carbon  points  in 
an  electric  lamp.  The  source  of  light  in  an  electric 
arc  lamp. 

ARMATURE.  That  part  of  a  dynamo-electric  machine  in 
which  the  useful  currents  are  generated.  It  is  the 
which  affects  atoms,  molecules  and  masses,  so  that 
they  will  come  together. 

Magnetic.     The  mutual  attraction  of  the  opposite  poles 
of  a  magnet. 

Axis.     An  imaginary  line  passing  through  a  body,  which 

may  be  supposed  to  revolve  around  it. 
Magnetic.     A  straight  line   drawn   through   a    magnet, 
joining  its  poles. 

shaft  or  central  revolving  arm  of  an  electric  generator, 
A  piece  of  iron  placed  on  the  poles  of  a  magnet  to 
preserve  or  keep  the  magnetism. 

ASYMPTOTE.  A  curved  line  which,  though  continually  ap- 
proaching a  straight  line,  never  meets  it. 

ATMOSPHERE.  The  mass  of  air  that  envelopes  the  earth. 
A  pressure  of  a  gas  or  fluid  equal  to  15  pounds  per 
square  inch. 

ATOM.     The  smallest  quantity  of  simple  matter  which  exists. 


567 
ATTRACTION.     That  force  which  draws  together;  the  cause. 


BALANCE,  ELECTRIC.  An  instrument  for  measuring  the 
vahie  of  electrical  resistance, 

BARAD.  The  unit  of  electrical  pressure.  It  is  equal  to  one 
degree  per  square  centimetre. 

BAROMETER.  An  instrument  for  measuring  the  pressure  of 
the  atmosphere. 

BATTERY.  When  applied  to  steam  boilers  it  is  the  combina- 
tion or  coupling  of  two  or  more  steam  boilers,  so  as  to 
act  as  one  steam  source.  When  applied  to  dynamo- 
electric  machines  it  means  that  two  or  more  separate 
machines  are  combined  so  as  to  act  as  a  single  elec^ 
trie  source.  * 

BATTERY,  ELECTRIC.  The  combination,  as  a  single  source, 
of  two  or  more  electrical  sources.  The  term  battery 
is  sometimes  used  to  designate  a  single  voltaic  cell, 
but  this  is  incorrect.  One  electric  battery  may  con- 
sist of  a  combination  of  two  or  more  Leyden  jars; 
two  or  more  separate  magnets;  two  or  more  primary 
cells;  two  or  more  secondary  or  storage  cells. 

Bl-FiLAR.  Two  fibers.  When  used  in  connection  with 
the  term  suspension,  it  indicates  that  the  needle  or 
magnet  is  suspended  by  two  instead  of  one  fiber;  when 
used  to  designate  the  winding  of  a  coil  (bi-filar  wind- 
ing of  coils),  it  means  that  the  coil  is  wound  in  such 
a  way  that,  instead  of  being  wound  in  one  continuous 
length,  the  wire  is  doubled  on  itself,  and  then  wound. 

BINARY  COMPOUND.  A  chemical  compound  formed  of  two 
different  elements.  ^ 

BOBBIN.  An  insulated  coil  of  wire — capable  of  rotation—, 
for  an  electro  magnet. 

BRIDGE  MAGNETIC.  A  device  for  measuring  magnetic-resis* 
tance,  similar  to  an  electric  balance. 


568 

BROKEN  CIRCUIT.     An  open  circuit. 

B.  &  S.     An  abbreviation  for  Brown  &  Sharpe's  wire  gauge. 

B.  W.  G.     An  abbreviation  for  Birmingham  wire  gauge. 


CALIBER.     The  inner  diameter;  bore. 

CALORIC.  A  term  applied  to  that  something  supposed  to  be 
the  cause  of  heat. 

CALORIMETER.  A  device  for  measuring  the  quantity  of 
heat. 

CAM.     An  eccentric;  sometimes  called  camb  or  wiper. 

CANDLE,  STANDARD.  A  candle  of  a  definite  composition 
which  will  produce  a  definite  amount  of  light,  used  for 
comparative  measurement. 

CAPILLARITY.  A  term  used  to  designate  the  elevation  of 
liquids  in  small  tubes. 

CARCEL.     French  unit  of  illuminating  power. 

A  jar  containing  the  elements  and  liquid  of  a  bat- 
tery. The  combination  of  two  metals  (elements)  and 
&  liquid  or  liquids  in  such  a  manner  as  to  produce  a 
current  of  electricity. 

C.  (J,  S.  SYSTEM.  Cruti-meter — gramme — second  system, 
used  to  designate  the  absolute  system  of  units. 

CENTRIFUGAL  FORCE.  The  force  which  tends  to  urge  a 
rotating  or  whirling  body  directly  away  from  the  center 
of  rotation. 

CHAMFER.     A  bevel. 

CIRCUIT.     The  path  of  an  electric  current. 

CLOSURE.     Completing  an  electrical  circuit. 

COIL.  The  arrangement  of  an  insulated  wire  in  symetrical 
convolutions,  through  which  an  electric  current  can 
pass. 

Resistance.     Coils  of  wire  of  known  resistance  for  measur- 
ing fhe  resistance  of  any  current. 


569 

COMMUTATOR.  That  part  of  a  dynamo-electric  machine 
which  collects  the  currents  generated,  and  changes  the 
direction  of  these  currents. 

CONDENSER.  A  device  for  condensing  a  large  amount  of 
electricity  on  a  small  surface. 

CONDUCTIVITY.  The  ability  to  convey  electricity;  opposite 
of  resistance. 

CONDUCTORS.  Anything  which  will  convey  an  electric  cur- 
rent. 

CORE.     The  iron  of  an  electro-magnet. 

COULOMB.    The  unit  of  electrical  quantity. 

CURRENT.     The  flow  of  electricity  in  a  conductor. 
Alternating.     A  current  which  periodically  reverses. 
Continuous.     A  current  which  does  not  change  its  direc- 
tion. 


DASH-POT.  A  mechanical  device  for  checking  a  sudden 
motion,  by  means  of  a  plunger  working  against  a 
cushion  of  air,  water,  or  spring. 

DIAPHRAGM.  A  thin  plate  or  partition  placed  across  a  tube 
or  other  hollow  body;  a  disk ;  a  flat  circular  piece. 

DIFFERENCE  OF  POTENTIAL.  A  term  used  to  designate  that 
part  of  the  electro-motive  force  which  exists  between 
any  two  points  in  a  circuit. 

DIP,  MAGNETIC-  The  inclination  of  a  magnetic  needle  to- 
ward the  earth. 

DYNAMO.     A  machm-e  which  furnishes  electricity. 

DYNAMOMETER.  A  device  for  measuring  the  power  of  an 
engine  or  motor. 

DYNE.     The  unit  of  electrical  force 


ECCENTRIC.  Out  of  center;  a  modification  of  a  crank;  a 
circular  plate  attached  to  a  revolving  shaft,  but  not 
having  the  same  center,  for  producing  an  alternat- 
ing motion. 

ELECTRICITY.  That  which  is  the  cause  of  electric  phenom- 
enon. 

ELECTRODES.  Literally,,  roads  for  electricity.  The  poles  of 
a  battery.  See  anode  and  kathode. 

ELECTROLYTE.  A  liquid  which  permits  an  electric  current  to 
pass  through  it,  only  by  means  of  the  decomposition 
of  this  liquid. 

Electrolysis.     Chemical  decomposition  effected  by  means 
of  an  electric  current. 

ELECTRO-MAGNET.  A  magnet  produced  by  passing  a  cur- 
rent of  electricity  around  a  soft  iron  core. 

E.  M.  F.     Electro-motive  force. 

ELEMENT.     Matter  which  cannot  further  be  decomposed. 
Voltaic.     One  of  the  metal  or  substances  in  a  cell. 

ENERGY.     The  power  of  doing  work. 

ERG.     The  unit  of  electrical  work. 


FARAD.     The  unit  of  electrical  capacity. 

FIELD,  MAGNETIC.  That  space  surrounding  the  poles  of  a 
magnet  which  is  within  the  magnetic  influence. 

FILAMENT.  The  thread  of  carbon  in  an  incandescent  elec- 
tric lamp,  which  is  the  source  of  light  for  the  lamp. 
The  carbon  becomes  luminous  owing  to  its  resistance 
against  the  passage  of  the  electric  current  through  it. 

Focus.  The  point  in  front  or  back  of  a  lens  or  mirror  where 
the  rays  of  light  meet. 

FOOT-POUND.     A  unit  of  work. 

FORCE.  That  which  produces  a  change  in  the  condition  ©f 
rest  or  motion  of  the  body. 


TORMUL/E.     Mathematical    expressions    for    some    general 

rule  or  principle. 
FRICTION.     The   resistance   occasioned   to    the    motion   of 

bodies  by  the  pressure  of  their  surface   against  each 

other. 
FULCRUM.     Anything  which    supports   a   lever,  or   against 

which  a  lever  presses  in  exerting  its  force. 


GALVANISM.  A  term  to  expres  the  effects  of  voltaic  elec- 
tricity. 

GALVANOMETER.  A  device  for  measuring  the  strength  of 
an  electrical  current. 

GAUSS.     The  unit  of  intensity  of  a  magnetic  field. 

GRAVITY.  The  force  which  causes  masses  c*f  matter  to  tend 
to  move  toward  each  other. 


HELICES.  Coils  of  wire  which  acquire  all  the  properties  of 
a  magnet  when  traversed  by  an  electrical  current. 

HYDRODYNAMICS.  That  branch  of  general  mechanics  which 
treats  of  the  equilibrium  and  motion  of  fluids. 

HYDROSTATICS.     Same  as  hydrodynamics. 


572 

IMPACT.     The  effect  of  a  blow  or  stroke  from  one  source  to 

another,  whether  in  motion  or  at  rest. 

IMPETUS.     Effect  produced  by  the  velocity  of  a  moving  body. 
IMPONDERABLE.     Possessing  no  weight. 
INCANDESCENSE,  ELECTRICAL.      The  electric  heating  of  a 

solid  to  luminosity. 
INERTIA.     That  property  of  matter  which  tends  to  cause 

matter  when  at  rest  to  remain  so. 


JACK  ARCH.     An  arch  the  thickness  of  one  brick. 

JACK-SCREW.  A  lifting  instrument  which  acts  by  the  rota- 
tion of  a  screw  in  a  threaded  socket. 

JAG.     A  dovetail  or  barb. 

JAG-BOLT.     One  with  a  barbed  shank. 

JAMB.  The  upright  sides  of  a  doorway,  frame,  window  or 
fire-place. 

JAM-NUT.  A  check-nut,  a  lock-nut.  One  nut  screwed  down 
upon  another  nut  to  hold  it. 

JOURNAL.  That  part  of  an  axle  or  shaft  which  rests  on  the 
bea-ings. 

JOULE.     The  unit  of  heat — electrical 


KATHCBR.     The  negative  pole  or  electrode  of  a  battery. 
KEY.     A  wedge    piece  of   iron    or  steel  for  holding 
pulleys  in  place. 


573 

.  A  slot  in  the  centers  of  pulleys  or  on  a  shaft,  for 
the  reception  of  a  key,  which  holds  the  pulley  or  wheel 
in  place. 

KINETIC  ENERGY.     Is  the  work  a  body  can  do  in  virtue  of 
its  motion. 


LAP.  Is  the  space  which  the  slide  valve  advances,  on  the 
steam  side,  beyond  the  opening  of  the  steam  port  after 
it  has  closed  it,  and  is  given  for  the  purpose  of  causing 
the  engine  to  work  expansively  by  cutting  off  the 
admission  of  steam  before  the  end  of  the  stroke. 

LAP-WELD.  A  weld  in  which  the  welding  edges  are  thinned 
down,  lapped  and  welded. 

LEAD.  An  arrangement  of  the  ports  of  a  steam-valve  by 
which  steam  is  admitted  in  front  of  the  piston  a  little 
before  the  end  of  the  piston  stroke;  also  an  arrange- 
ment of  the  ports  to  provide  for  the  escape  of  the 
steam  from  behind  the  piston  before  the  completion  of 
the  stroke.  When  on  the  steam  side  it  is  called  outside 
lead,  when  on  the  exhaust  side  it  is  inside  lead. 

LENS.  A  piece  of  transparent  substance  (usually  glass) 
fashioned  into  a  shape  affording  two  regular  opposite 
surfaces,  both  curved,  or  one  curved,  and  the  other 
plane,  by  which  the  direction  of  rays  of  light  are 
changed,  diminishing  or  increasing  the  apparent  size  of 
objects  viewed  through  them. 

LEVER.  A  bar  or  other  rigid  device  having  a  fixed  point,  or 
fulcrum,  in  the  use  of  which  an  increase  of  power, 
speed  or  facility  is  gained  in  lifting  or  other  exercise 
of  power.  When  the  fulcrum  is  between  the  weight 
and  power,  the  lever  is*  of  the  first  class;  when  the 
fulcrum  is  opposite  the  power,  the  lever  is  of  the 
second  class;  when  the  fulcrum  is  opposite  the  weight, 
the  lever  is  of  the  third  class. 


574 

LINK  MOTION.  A  gear  by  which  the  steam-valve  of  a  loco- 
motive or  engine  is  operated,  so  that  a  reversible 
motion  may  be  secured. 

LIVE  STEAM.     Steam  direct  from  the  boiler  at  full  nressure. 


MAGNET.     A  body  possessing  the  power  of  attracting  iron, 

steel,  etc. 

Electro.     A  magnet  produced  by  the  passage  of  a  cur- 
rent of  electricity  around  a  core  of  soft  iron. 

MALLEABLE.  Capable  of  being  hammered  out  into  thin 
plates. 

MASS,     The  quantity  of  matter  contained  in  a  body. 

MATTER.  That  which  occupies  space,  and  prevents  other 
matter  from  occupying  the  same  space  at  the  same 
time.  Matter  is  composed  of  atoms,  which  unite  to 
form  molecules. 

MOLECULE.  The  smallest  portion  of  matter  capable  of  being 
divided.  • 

MOMENTUM.  Is  the  rate  of  change  of  velocity— and  may  be 
either  positive  or  negative. 

MOVER-PRIME.  The  initial  motor,  or  that  which  drives 
secondary  movers. 


NEGATIVE.  Opposite  to  positive.  One  of  the  phases 
(not  k'nds)  or  states  of  electrical  excitement. 

NON-CONDUCTORS.  Insulators.  Substances  which  offer 
considerable  resistance  to  the  passage  of  electricity. 


575 

OHM.     The  unit  of  electrical  resistance. 

©HMMETER.    A  device  for  measuring  electrical  resistance. 

OPTICS.     That  branch  of  natural  science  which  treats  of  the 

eye  or  vision. 

ORIFICE.     An  opening;  aperture. 
OSMOSE.     The  unequal  mixing  of  fluids  of  different  densities 

through  the  pores  of  a  separating  medium. 


PARAMAGNETIC.     Substances  possessing  magnetic  qualities. 
POSITIVE.     Opposite  to  negative.     One  of  the  phases  (not 

kinds)  or  states  of  electrical  excitement. 
POTENTIAL.     The  power  of  doing  electrical  work.     Electric 

level. 
POWER.     Rate  of  doing  work. 


FADIATION.     The  transference  of  energy  by  means  of  ether 

waves. 
R  ECIPROCALS.     The  quotient  arising  from  dividing  unites  by 

any  number. 
R  fcsuLTANT.     A  force  which  represents  the  effect  of  two  or 

more  forces  acting  in  different  directions. 


576 

SHUNT.  A  branch  or  additional  current  provided  at  any  part 
of  a  circuit;  a  short  circuit. 

SOLENOID.  A  cylindrical  coil  of  wire,  each  convolution  of 
which  is  a  circle,  and  which  acquires  all  the  properties 
of  a  magnet  when  traversed  by  an  electrical  current. 


TENACITY,     The  quality  of  holding  fast. 

TENSE.     Strained  tight;  taut. 

TENSION.     Act  or  degree  of  stretching;  elastic  power. 

TERTIARY.     Third,  of  the  third  formation  or  power. 

TORSION.     Act  of  twisting;  state  of  twist. 


VACUUM.     A    space   from  which   all   air   or   gas   has    been 

removed. 
VELOCITY.     The  rate  of  motion.     It  involves  the  idea  of 

direction  as  well  a§  magnitude.     It  is  uniform  when 

the  rate  of  motion  does  not  change. 
VIBRATION.     A  to  and  fro  motion. 
VOLT.     The  practical  unit  of  electromotive  force. 


WATT.     The  volt-ampere  or  unit  of  electrical  work. 
WORK.     That  which  is  done  by  a  force.     It  is  the  product  of 
the  force  and  the  distance  through  which  it  acts. 


UNIVERSITY    OF    CALIFORNIA 
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